A rather startling fact which studies bear out is: Indoor air is generally 10 times more polluted than the outdoor air. So, where do we go? India has 13 of the world’s 20 most polluted cities, Delhi being on the top of all.
The presence of PM2.5 in Delhi’s air is an average of 153 micrograms per cubic metre against a safe national level of 60 micrograms per cubic metre and Ozone is 2/3 times the normal. More than 50 percent of Delhi’s vehicles run on diesel. We have dirty diesel with high sulphur content and this does not allow for diesel particulate filters (DPF) to be installed on the vehicles to reduce NOx (Nitrogen Oxide) and PM2.5 levels to acceptable ones.
This is the main cause of the problem. We need EURO 6 compliant vehicles and diesel with less than 10 ppm of Sulphur so that the DPF filters can work. The technology and capacity exist for such fuel and vehicles. It is a question of our will and priority to solve the problem.