India, Sept. 29 -- From Thursday, fuel stations across Delhi-National Capital Region will stop selling fuel to vehicles without a valid Pollution Under Control (PUC) certificate. The Commission for Air Quality Management (CAQM), the panel that coordinates pollution control measures in Delhi and its neighbouring areas, ordered in May that "no fuel shall be dispensed" to such vehicles, with number-plate cameras or other technology to enforce it.

Delhi ran a version of the rule last December, when more than 3,700 vehicles were fined on the first day.

The certificate records a test that checks two gases in petrol cars while the engine idles, and the darkness of exhaust smoke in diesel ones.

Research has repeatedly found that this approach ...