Need to upgrade PUC norms
Pollution Under Control (PUC) testing system does not measure nitrogen oxides (NOx) and particulate matter (PM), including PM2.5. The existing PUC tests primarily assess carbon monoxide (CO) and hydrocarbons (HC) for petrol vehicles, while for diesel vehicles, they measure smoke opacity using the Hartridge Smoke Unit (HSU), an outdated proxy for particulate content. more