Newer, stricter PUC norms likely including digitally signed results from vehicle emission standards

India’s pollution-under-control (PUC) testing system could see tighter safeguards against manipulation, with a proposed amendment to vehicle emission-testing standards requiring testing equipment to digitally sign results and transmit them directly to a central government server.

A sprinkler sprays water to settle dust amid pollution on Wednesday. (Sanjeev Verma/ HT Photo)The October 2026 amendment to the Automotive Industry Standard (AIS)-137 (Part 8), issued under the Central Motor Vehicles Rules, proposes introducing hardware-based security features in petrol and diesel vehicle emission-testing equipment to ensure that readings cannot be altered by operators or external devices.

Also Read I Over 4.5 lakh PUC challans issued in Delhi till Oct 27: Traffic police data Under the proposed framework, gas analysers and smoke meters will have to incorporate a dedicated Trusted Platform Module (TPM 2.0) security chip to generate and store cryptographic keys.

Every valid emission test will have to be digitally signed within the instrument before its results are transmitted to the Pollution Under Control Certificate (PUCC) server through the machine’s own SIM or eSIM connection.

The amendment also seeks to prevent computers at testing centres from manipulating readings. The local computer will be restricted to initiating tests and handling the printing of certificates, without access to the instrument’s private signing key or the ability to modify measured emission values.

Wi-Fi and the computer’s internet connection cannot be used to transmit test data. The existing digital PUC system links test results to the VAHAN database, with NIC-developed testing software implemented in 31 states, according to the Ministry of Road Transport and Highways.

Features include geo-fencing of testing centres, vehicle photographs and videos, and real-time reporting. “The test results are updated in Vahan system on real-time basis,” the ministry said. The proposed standards also prescribe stricter testing protocols.

Measurements will have to be conducted for at least 60 seconds, with the average of readings during the final 10 seconds taken as the result. Live readings will not be displayed during measurement, except engine speed. Tests recording oxygen concentrations of 5% or higher will be rejected, with operators required to conduct a retest.

Every valid completed test, irrespective of whether a vehicle passes or fails, will have to be digitally signed and transmitted to the central server. Also Read I No PUCC, no entry into Delhi from Nov 1: What the test measures, and pollutants it cannot trace The instruments will also be required to detect unauthorised opening, software modifications and attempts to manipulate readings.

Such incidents will trigger suspension of further testing and signing until the equipment is reverified. The amendment provides for manufacturers to register their equipment and maintain records of active and withdrawn instruments.

It also includes provisions for audit logs and reporting of security incidents.