``Being a complicated multi-dimensional problem, air pollution is a difficult subject beginning from the adulteration of petrol to improper engine tuning,'' Chahande said after addressing a meeting with NGOs and government agencies in the city today.

Among the various measures that will be implemented in the next few months are the setting up of a control room manned by the Regional Transport Office (RTO) where citizens can register numbers of polluting vehicles. A follow-up cell is to be formed to obtain compliance.

The collector has already advised the RTO and traffic police to undertake on-the-spot action for suspension of the registration of pollutant vehicles after a 15-day public notice.

A public interest notification is also to be issued shortly givingthem a deadline of May 1 to get their PUC certificates. Thereafter, offenders will be chased by flying squads from the RTO and traffic police, and their registration suspended. The vehicles will then be sent immediately to authorised PUC centres.

Other decisions taken by the collector today include the joint inspection for adulteration of petrol samples by representatives of NGOs, collectorate officials and controller of rationing officials.

Speaking on the campaign against air pollution, Chahande said the first two steps are to identify the problem at various levels, which has already begun. The documentation strategy is to be the second phase of the programme which will finally be followed by the implementation phase of actual pollution control checks and increase in the number of mobile PUC centres.

The collectorate will also begin a massive awareness campaign in cooperation with various agencies next month.

The collector said the ultimate solution, the introduction of vehicles fuelled byCompressed Natural Gas (CNG), had its own logistical problems.

But other long-term measures being contemplated include the gradual phase-out of two stroke engines and the ban on sale of second hand engines, a major source of inefficient fuel combustion.

A recent study by the Indian Society of Environmental Science and Technology had found alarming levels of carbon monoxide in various junctions in Mumbai. The level of carbon monoxide was recorded at 15-20 parts/million (ppm) at Saki Naka, Byculla, Mumbai Central and Sion, which is three times the permissible level -- 5 ppm.

Nearly seventy per cent of the 600 tonnes of pollutants belched into the city come from the exhaust pipes of vehicles. There are 8.5 lakh vehicles in the city, and 200 new vehicles are registered at the four RTOs every day.