**Executive Summary**
This document lists OCEMS (Online Continuous Emission Monitoring Systems) models that have been issued with NPL (National Physical Laboratory) verification certificates or provisional letters of confirmation. The list is updated with various dates, with the latest update on February 19, 2026. The document includes certificate holders, certificate types, model numbers, gases/dust measured, certificate numbers, and contact details of the certificate holders.
**Key Points / Main Content**
* **Verification Certificates and Provisional Letters:**
* The document lists OCEMS models that have been issued either verification certificates or provisional letters of confirmation.
* **OCEMS Model Details:**
* Each entry includes the certificate holder, certificate type, model number, gases/dust measured, and the NPL certificate number.
* **Certificate Updates:**
* The list is updated periodically, with the latest update on February 19, 2026.
* Notes indicate where revised certificates are enforced or vendors are removed/unauthorized to use certificates.
* **Important Notes:**
* Specific notes indicate when a newer verification certificate supersedes a previous one.
* Advance Enviro Solutions is removed as an authorized vendor (Sr. No. 35).
* **Contact Details:**
* The final section of the document lists contact details (email and phone number) for each certificate holder.
**Impact Analysis**
**Stakeholder:** Certificate Holders
* **Impact:** Must ensure that their OCEMS models listed have valid and up-to-date NPL verification certificates or provisional letters of confirmation. They must check for any updates regarding the validity of their certificates and adherence to the guidelines provided by NPL. They are also responsible for providing up to date contact details.
* **Action Required:** Verify the details of their certificates in the document, ensure the contact information is correct, and comply with any additional notes or revisions regarding their certificates or vendor status.
**Stakeholder:** NPL
* **Impact:** Maintain and update the list of OCEMS models with verification certificates or provisional letters of confirmation.
* **Action Required:** Update and maintain the list, and inform the certificate holders.
**Stakeholder:** Regulators/Environmental Agencies
* **Impact:** Rely on this list to ensure that OCEMS models used for emission monitoring meet the NPL verification standards.
* **Action Required:** Regularly check the list for the latest updates and enforce the use of verified OCEMS models.
**Stakeholder:** End Users of OCEMS
* **Impact:** Need to use OCEMS models with valid NPL verification to ensure accurate and reliable emission monitoring data.
* **Action Required:** Verify that the OCEMS models used are listed in the document and have valid certificates.
Key Entities Referenced
NPLI CS/CEMS/VC : Refers to National Physical Laboratory India Certification Scheme / Continuous Emission Monitoring System / Verification Certificate, the certificate names of various devices.
NPLI CS/PM-CEMS/VC : Refers to National Physical Laboratory India Certification Scheme / Particulate Matter - Continuous Emission Monitoring System / Verification Certificate, the certificate names of various devices.
NPLI CS/PM_CEMS/PLoC : Refers to National Physical Laboratory India Certification Scheme / Particulate Matter - Continuous Emission Monitoring System / Provisional Letter of confirmation, the certificate names of various devices.
NPLI CS/CEMS/PLOC : Refers to National Physical Laboratory India Certification Scheme / Continuous Emission Monitoring System / Provisional Letter of confirmation, the certificate names of various devices.
OCEMS : Online Continuous Emission Monitoring Systems
See Full Document Text
List of OCEMS models issued with NPL verification certificate/provisional letter of confirmation
Sr. No. Certificate Holder Certificate Type Model No. Gases/Dust Certificate
As on 21.11.2025
SO2
1 PRIMA Equipment Verification Certificate PSGM-1-D-AGS NO NPLI CS/ CEMS/ VC-2025-11
SO2
NO2
NH3
NO
Formaldehyde
Phenol
2 NEVCO Engineers Pvt Ltd. Verification Certificate AR602Z NPLI CS/ CEMS/ VC-2025-01S *1
(UV)/NHg/N H2O
*1
*1
CO
HCl
NEVCO Engineers Pvt Ltd. HF
3 Verification Certificate AR650/N *2 H2O NPLI CS/ CEMS/ VC-2025-02S *2
CO2*2
CH4*2
4 Sintrol Oy Verification Certificate S305QAL PM NPLI CS/ PM-CEMS/VC-2025-
03A *3
5 NEVCO Engineers Pvt. Ltd. Verification Certificate O2000 O2 NPLI CS/ CEMS/ VC-2025-04S *4
SO2
NO
CO
ACE GASANALYSERS
6 PRIVATELIMITED Provisional Letter of Confirmation ACE10000XXHE CO2 NPLI CS/ CEMS/ PLoC-2025-16
SO2
NO
7 Endress+Hauser India Verification Certificate S700 CO NPLI CS/ CEMS/ VC-2025-08
8 Endress+Hauser India Verification Certificate FWE200DH PM NPLI CS/ PM-CEMS/VC-2025-09
Endress+Hauser (India) Pvt.
9 Ltd. Verification Certificate SB 100 PM NPLI CS/ PM-CEMS/VC-2025-05
Endress+Hauser (India) Pvt.
10 Ltd. Verification Certificate SP 100 PM NPLI CS/ PM-CEMS/VC-2025-07
Endress+Hauser (India) Pvt.
11 Ltd. Verification Certificate SP30 PM NPLI CS/ PM-CEMS/VC-2025-06
Endress+Hauser (India) Pvt.
12 Ltd. Verification Certificate SB30 PM NPLI CS/ PM-CEMS/VC-2025-10
13 Envea India Private Limited Verification Certificate PCME QAL 181 PM NPLI CS/ PM-CEMS/VC-2025-12
14 Envea India Private Limited Verification Certificate DM 170 PM NPLI CS/ PM-CEMS/VC-2025-13
CO
NOx
SO2
ENDA
CO2
15 Horiba India Pvt. Ltd. Verification Certificate 5000Series O2 NPLI CS/ CEMS/VC-2025-21
SO2
Envirozone Pvt. Ltd. NO
16 (Envirozone
CO
Instruments& Verification Certificate ZPA-CEMS O2 para
Equipments Pvt.Ltd.) CO2
NPLI CS/ CEMS/VC-2025-22
O2 (ZrO2)
SO2
Envirozone Pvt. Ltd. NO
17 (Envirozone CO
Instruments& Verification Certificate ZRE - ZRE/ZFK 7 O2 (Pa)
Equipments Pvt.Ltd.) O2 (Zi) NPLI CS/ CEMS/VC-2025-23
DURAG India
18 Instrumentation Pvt. Ltd. Verification Certificate D-R-290 PM NPLI CS/ PM-CEMS/VC-2025-24
DURAG India
19 Instrumentation Pvt. Ltd. Verification Certificate D-R-320 PM NPLI CS/ PM-CEMS/VC-2025-25
DURAG India
20 Instrumentation Pvt. Ltd. Verification Certificate HM 1400 TRX Hg NPLI CS/CEMS/VC-2025-26Envirozone Pvt. Ltd.
(Envirozone
21 Instruments& Provisional Letter of EZ 320- P NPLI CS/PM_CEMS/PLoC-2025-28
Equipments Pvt. Ltd.) confirmation PMLS M
Important Note:
*1 Henceforth, the verification certificate no. NPLI CS/CEMS/VC-2025-01S is enforced in place of the verification certificate no. NPLI CS/CEMS/VC-2025-
01
*2 Henceforth, the verification certificate no. NPLI CS/CEMS/VC-2025-02S is enforced in place of the verification certificate no. NPLI CS/CEMS/VC-2025-
02
*3 Henceforth, the verification certificate no. NPLI CS/PM-CEMS/VC-2025-03A is enforced in place of the verification certificate no. NPLI CS/PM-
CEMS/VC-2025-03
*4 Henceforth, the verification certificate no. NPLI CS/CEMS/VC-2025-04S is enforced in place of the verification certificate no. NPLI CS/CEMS/VC-2025-
04
Sr. No. Cirtificate Holder Certificate Type Model No. Gases/Dust Certificate Number
List Updated on 01.12.2025
22 Envea India Private Limited Verification Certificate DM 210 PM
NPLI CS/ PM-CEMS/VC-2025-14
MIR9000e CO
NOx as NO2
N2O
SO2 NPLI CS/ CEMS/VC-2025-15
CH4
O2
23 Envea India Private Limited Verification Certificate
CO2
24 Envea India Private Limited Verification Certificate SC 600T/ PCME Stack 602 PM NPLI CS/ PM-CEMS/VC-2025-17
25 Envea India Private Limited Verification Certificate PCME QAL 182 WS PM NPLI CS/ PM-CEMS/VC-2025-18
26 Forbes Marshall Verification Certificate D-CEM2100 PM NPLI CS/ PM-CEMS/VC-2025-19
CO
NO NPLI CS/ CEMS/VC-2025-20
27 Forbes Marshall Verification Certificate FMGCEM40XX (GCEM-40) SO2
List Updated on 10.12.2025
28 SARTECH INTL (LAND UK) Verification Certificate 4500 MkIII PM NPLI CS/PM-CEMS/VC-2025-29
Envirozone Pvt. Ltd.
Provisional Letter
29 (Envirozone Instruments& EZ 320-PM PM NPLI CS/PM-CEMS/PLoC-2025-30
of
Equipments Pvt. Ltd.)
confirmation
ACOEM ECOTECH
30 INDUSTRIES Verification Certificate Serinus 30 CO NPLI CS/CEMS/VC-2025-31
PRIVATE LIMITED
ACOEM ECOTECH
NO
31 INDUSTRIES Verification Certificate Serinus 40 NPLI CS/CEMS/VC-2025-32
PRIVATE LIMITED NO2
ACOEM ECOTECH
32 INDUSTRIES Verification Certificate Serinus 50 SO2 NPLI CS/CEMS/VC-2025-33
PRIVATE LIMITED
.. to be cont. in next pageSr. Certificate Holder Certificate Type Model Gases/Dust Certificate
No. No. Number
List Updated on 12.12.2025
33 PM
Bhoomi Process Management Pvt. Provisional Letter of
Ltd. confirmation BI 7010 NPLI CS/PM-
CEMS/PLoC-2025-34
34 PM
Bhoomi Process Management Pvt. Provisional Letter
Ltd. of confirmation BI 7020 NPLI CS/PM-
CEMS/PLoC-2025-35
PM
35 Verification Certificate SOx NPLI CS/CEMS/VC-
Advance Enviro Solutions Gaz-CEMS and NOx
2025-36 *5
Gaz-
SPM
SO2
NO
36 Envirozone Pvt. Ltd. (Envirozone Provisional EZ 320-NDIR CO NPLI CS/CEMS/PLoC-
Instruments & Equipments Pvt. Letter of 2025-37
Ltd.) confirmation
CO
NO
SO2
Verification Certificate CO2
37 ABB India Limited EL 3000- O2 NPLI CS/CEMS/VC-
Uras26 (Electrochemical) 2025-38
O2 (Paramagnetic)
CO
NO
NO2
N2O
SO2
HCl
HF
Verification Certificate
NH3
ABB India Limited
H2O
CO2
38 ACF 5000 NPLI CS/CEMS/VC-
H2CO
Series 2025-39
CH4
TOC (FID)
O2 (ZrO2)
CO
NO
NO Version (L)
SO2
ABB India Limited Verification Certificate AO 2000 Series N2O
39 NPLI CS/CEMS/VC-
CO2
2025-40
O2
40 Verification Certificate NPLI CS/CEMS/VC-2025-
ABB India Limited FMD 09 Series Waste Gas Velocty
41
CO
CO2
NO
NO2
N2O
NH3
ABB India Limited SO2
Verification Certificate MCA 10 HCl
H2O
Series
CH4
41 NPLI CS/CEMS/VC-
TOC
O2 2025-42
CH2O
Verification Certificate
42 ABB India Limited PFM 20/20F NPLI CS/PM-CEMS/VC-
Series PM 2025-43
*5 Henceforth, for verification certificate no. NPLI CS/CEMS/VC-2025-36, a revised copy of the certificate is enforced.
Henceforth (08.02.2026) - M/s Advance Enviro Solutions the vendor mentioned at Sr. No. 35 has been removed and not authorized to
use the Verification Certificate No. NPLI CS/CEMS/VC-2025-36; dated 12 December 2025.Sr.
No. Certificate Holder Certificate Type Model No. Gases/Dust Certificate Number
Updated on 27.12.2025
Engineering and
Provisional Letter NPLI CS/PM-CEMS/PLoC-
43 Environmental EE-SPM-100-BS PM
of confirmation 2025-44
Solutions Pvt. Ltd.
Provisional Letter NPLI CS/PM-CEMS/PLoC-
44 Aadhav Intech LM-318 PM
of confirmation 2025-45
SWAN
Provisional Letter NPLI CS/PM-CEMS/PLoC-
45 LM3189 PM
environmental Pvt.
of confirmation 2025-46
Ltd.
CO
CO2
SO2
NO
Thermo Fisher
NO2
Verification
46 Scientific India Pvt. MAX-iR FTIR N2O
Certificate NPLI CS/CEMS/VC-2025-47
Ltd. NH3
HF
HCl
CH4
H2O
VOC
Thermo Fisher NO
Verification
47 Scientific India Pvt. 42i NPLI CS/CEMS/VC-2025-48
Certificate
Ltd. NO2
Thermo Fisher
Verification
48 Scientific India Pvt. 43i SO2 NPLI CS/CEMS/VC-2025-49
Certificate
Ltd.
UNISEARCH INDIA HF
Verification
49 INSTRUMENTS LasIR HF-HCl-H2O HCl NPLI CS/CEMS/VC-2025-50
Certificate
PRIVATE LIMITED H2O
UNISEARCH INDIA
Verification
50 INSTRUMENTS UIIPL–DOAS-SO2 SO2 NPLI CS/CEMS/VC-2025-51
Certificate
PRIVATE LIMITED
UNISEARCH INDIA
Verification LasIR for NH3
NH3
51 INSTRUMENTS NPLI CS/CEMS/VC-2025-52
PRIVATE LIMITED
Certificate and H2O H2O
PM
Verification Gaz-CEMS and
52 Eco System SOx NPLI CS/CEMS/VC-2025-53
Certificate Gaz-SPM
NOx
SO2
Analyser
Verification NO
53 InstrumentCo. Pvt. ZRE - ZRE/ZFK 7 NPLI CS/ CEMS/VC-2025-54
Certificate CO
Ltd.
O2 (Pa)Sr.
No. Certificate Holder Certificate Type Model No. Gases/Dust Certificate Number
Updated on 27.12.2025
O2 (Zi)
Vasthi Instruments Provisional Letter NPLI CS/PM-CEMS/PLoC-
54 VBDM-1500 PM
Pvt. Ltd. of confirmation 2025-55
Vasthi Instruments Verification
55 Vair-9001 SO2 NPLI CS/CEMS/VC-2025-56
Pvt. Ltd. Certificate
Vasthi Instruments Verification
56 Vair-9002 NO2 NPLI CS/CEMS/VC-2025-57
Pvt. Ltd. Certificate
CO
HCl
SO2
NO
CO
Envea India Private Verification 2
57@ NPLI CS/CEMS/VC-2025-58
Limited Certificate MIR9000 NO/NOx
(CLD)
O
2
CH
4
NO (CLD)
2
N O
2
Envea India Private Verification
58 GRAPHITE 52M TOC NPLI CS/CEMS/VC-2025-59
Limited Certificate
SO
GREEN ENVIRO 2
Verification
59 INTERNATIONAL PVT CEMS-2000 NO NPLI CS/CEMS/VC-2025-60
Certificate
LTD.
O
2
Provisional Letter of SO
2
SWAN confirmation (Lack
NO
60@ environmental Pvt. of Fit for CO2 & O2 SGA-900 NPLI CS/CEMS/PLoC-2025-61
Ltd. shows higher
CO
deviation)
SO
2
Adage Automation Verification O
61@ ULTRAMAT 23 2 NPLI CS/CEMS/VC-2025-62
Private Limited Certificate
NO
CO
Verification CO
Certificate (Lack of
NO
fit of SO2 Need to
Adage Automation
62@ clarified within 6 Ultramat/Oxymat 6 SO 2 NPLI CS/CEMS/VC-2025-63
Private Limited
months from the
date of issue of this O 2
certificate)
NH3
Adage Automation Verification
63 LDS 6 7MB6121 H2O NPLI CS/CEMS/VC-2025-64
Private Limited Certificate
HCL
@Details revised as per latest information dated 09.01.2026 & 15.01.2026 received from CSIR-NPL.Sr.
No. Certificate Holder Certificate Type Model No. Gases/Dust Certificate Number
Updated on 16.01.2026
Analyser Instrument Verification OPASTOP
64 PM NPLI CS/PM-CEMS/VC-2025-65
Co. Pvt. Ltd. Certificate GP4000H
Analyser Instrument Verification
65 GFS 390 SO NPLI CS/CEMS/VC-2025-66
2
Co. Pvt. Ltd. Certificate
Analyser Instrument Verification
66 GLN 390 NO NPLI CS/CEMS/VC-2025-67
x
Co. Pvt. Ltd. Certificate
Analyser Instrument Verification
67 GFC 390 CO NPLI CS/CEMS/VC-2025-68
Co. Pvt. Ltd. Certificate
Adage Automation Verification
68 FIDAMAT-6 TOC NPLI CS/CEMS/VC-2025-69
Private Limited Certificate
ACE GAS ANALYSERS Provisional Letter NPLI CS/PM-CEMS/PLoC-2025-
69 ACE10000BSC PM
PRIVATE LIMITED of confirmation 70
Provisional Letter DCEM6000 (Earlier NPLI CS/PM-CEMS/PLoC-2025-
70 Forbes Marshall PM
of confirmation known as ET301) 71
Provisional Letter PE-SPMMS-C91 NPLI CS/PM-CEMS/PLoC-2026-
71 PRIMA Equipment PM
of confirmation (tribo) 72
Provisional Letter NPLI CS/PM-CEMS/PLoC-2026-
72 PRIMA Equipment PE-SPMMS-C91 PM
of confirmation 73
CO
NO
NO
2
MIR 9000H
Envea India Private Verification SO 2
73 NPLI CS/CEMS/VC-2026-74
{(SO is unsuitable
Limited Certificate 2 NH
3
for the monitoring
of daily averages H 2O
at plants)
CO
2
(updated on
O
13.02.2026)} 2
CO
NO
SO
2
NO
2
N O
2
HCl
Envea India Private Verification
74 MIR -FT NH NPLI CS/CEMS/VC-2026-75
Limited Certificate 3
H O
2
HF
CO
2
O
2
CH
4
CHOHIMTB Engineers Pvt. Provisional Letter NPLI CS/PM-CEMS/PLoC-2026-
75 DLS DSL 340 PM
Ltd of confirmation 76
MKIII (updated
13.02.2026)
Drexel Electronics and
Provisional Letter NPLI CS/PM-CEMS/PLoC-2026-
76 Engineering Products DX4P-PM PM
of confirmation 77
Pvt ltd
Sr.
Certificate Holder Certificate Type Model No. Gases/Dust Certificate Number
No.
Updated on 13.02.2026
U3600-
77 ICE (Asia) Pvt. Ltd Verification Certificate PM NPLI CS/PM-CEMS/VC-2026-78
QAL1
NO
2
N O
2
NO
P2000
78 ICE (Asia) Pvt. Ltd Verification Certificate SO NPLI CS/CEMS/VC-2026-79
Series 2
CO
CO
2
H O
2
PCME
79 Envea India Private Limited Verification Certificate STACKFLOW Velocity NPLI CS/CEMS/VC-2026-80
200
STACKFLOW
80 Envea India Private Limited Verification Certificate Velocity NPLI CS/CEMS/VC-2026-81
400
NO
81 Envea India Private Limited Verification Certificate AC32e NPLI CS/CEMS/VC-2026-82
NO
2
Gases/
Sr. No. Certificate Holder Certificate Type Model No. Dust Certificate Number
Updated on 19.02.2026
Provisional Letter of i-DUSTHAWK
82 Innovative Technologies PM NPLI CS/PM-CEMS/PLoC-2026-83
confirmation 100
83 Envea India Private Limited Verification Certificate CO12e CO NPLI CS/CEMS/VC-2026-84
84 Envea India Private Limited Verification Certificate AF22e SO NPLI CS/CEMS/VC-2026-85
2Contact Details of Certificate Holders (updated 19.02.2026)
Sr.
Certificate Holder Email Contact No.
No.
1 PRIMA EQUIPMENT operations@primaequipment.com 8238030134
2 NEVCO ENGINEERS PVT LTD adish.kapur@nevcoengineers.com 9873246469
3 SINTROL OY vikram.singh@sintrol.com 9811676061
4 ACE GAS ANALYSERS PRIVATE LIMITED sam@acegasanalysers.com 9987824250
5 ENDRESS+HAUSER INDIA yugeshwari.devrukhkar@endress.com 8655715821
a.srivastava@envea.global/
6 ENVEA INDIA PRIVATE LIMITED r.kumar@envea.global 9311103004
7 HORIBA INDIA PVT. LTD. kunal.soni@horiba.com 9616747400
ENVIROZONE PVT. LTD. (ENVIROZONE
8 INSTRUMENTS & EQUIPMENTS PVT. LTD.) salesenvirozone@gmail.com 8076751198
DURAG INDIA INSTRUMENTATION PVT.
9 LTD. veer.kumar@durag.com 72045 37762
9503560565/
10 FORBES MARSHALL environ@forbesmarshall.com
982319967
11 SARTECH INT (LAND UK) in.sartech@gmail.com 9840082710
ACOEM ECOTECH INDUSTRIES PRIVATE
12 LIMITED harsh.dixit@acoem.com 7229044507
BHOOMI PROCESS MANAGEMENT PVT.
13 LTD. nayan@bhoomiltd.com 86522 97579
14 ADVANCE ENVIRO SOLUTIONS5 yash@advanceenviro.co.in 9891306306
15 ABB INDIA LIMITED salman.azeem@in.abb.com 9540190932
ENGINEERING AND ENVIRONMENTAL
16 SOLUTIONS PVT. LTD. Hamza@enggenv.com 9540990415
17 AADHAV INTECH admin@aadhavintech.com 9629466446
18 SWAN ENVIRONMENTAL PVT. LTD. karthik.b@swanenviron.in 9642225195
THERMO FISHER SCIENTIFIC INDIA PVT.
19 LTD. chandan.yadav@thermofisher.com 9810295553
UNISEARCH INDIA INSTRUMENTS
20 PRIVATE LIMITED service@unisearch-india.com 9025406630
21 ECO SYSTEM vppcpcb@gmail.com 9882810053
22 ANALYSER INSTRUMENT CO. PVT. LTD. aicpl.india@gmail.com 9772230061
23 VASTHI INSTRUMENTS PVT. LTD. prakash@vasthi.com 7382708685
24 GREEN ENVIRO INTERNATIONAL PVT LTD. sharon@greenenviro.co.in 8247649007
25 ADAGE AUTOMATION PRIVATE LIMITED pm@adage-automation.com 9867630715
26 IMTB ENGINEERS PVT. LTD spc@imtbengineers.com 9873560165
DREXEL ELECTRONICS AND ENGINEERING sales@drexel.in 9316660098
27 PRODUCTS PVT. LTD
28 ICE (Asia) Pvt. Ltd. Vahid.mirsaiidi@auburnfs.com 9788366251
29 Innovative Technologies shajig@innotech.co.in 8291846540
*5 Henceforth, for verification certificate no. NPLI CS/CEMS/VC-2025-36, a revised copy of the certificate is enforced.
Henceforth (08.02.2026)- M/s Advance Enviro Solutions the vendor mentioned at Sr. No. 35 has been removed and not authorized to use the Verification Certificate No.
NPLI CS/CEMS/VC-2025-36; dated 12 December 2025.