Most diesel vehicles in India do not meet the smoke density limit (65 on the Hartridge scale). But that's no cause for concern for owners. It's quite easy to carry home a pollution under control certificate (pucc) in India even if your vehicle does not conform to norms.

We at the Centre for Science and Environment know full well what a farce the pollution tests are. But we had hoped the new tests that came into effect from October 1, 2004 would improve matters. The tests were definitely more stringent: the earlier tests measured only the smoke emanating from the vehicles. But the new norms stipulated measurement of the warm up temperature of the engines as well as the measurement of engine speed. Moreover, the new smoke measurement instruments are controlled by sophisticated software