The National Green Tribunal is now planning to extend the ban on the sale of large diesel-powered vehicles in 11 more cities.
A decision on the same will be taken by the green body on Monday, according to a report in the Economic Times.
As per the report, the cities may include Mumbai, Kolkata, Bengaluru, Chennai and Hyderabad.
The automakers have reportedly termed the move "unscientific and uncalled for". The report added that according to the industry, such a widespread ban on large diesel cars would make investments made by several manufacturers "useless" and lead to loss of employment.
The registration of new vehicles with 2-litre or larger diesel engine has been banned by the Supreme Court in the National Capital Region comprising Delhi and its surrounding areas since 2015.
Earlier this month, the NGT had ordered the Kerala government to stop registering diesel vehicles with engine capacity of 2,000cc and above, except public transport and local authority vehicles.
The Kochi Circuit Bench of the NGT also barred all 10-year-old diesel vehicles - light and heavy - from plying on the roads of six cities. The Kerala High Court stayed the NGT order on new vehicles, but did not interfere with that covering old ones.
Overall, industry experts say, about 4 lakh diesel vehicles with 2-litre or larger engines are sold in the country annually. The ban in the NCR has already resulted in a production loss of 11,000 vehicles, affecting 5,500 jobs, including at dealerships, according to the Society of Indian Automobile Manufacturers (SIAM). Had the ban been countrywide, it would have led to a loss of 47,000 jobs, it estimates.
According to a statement issued by industry body Society of Indian Automobile Manufacturers (SIAM) in May this year, the ban on diesel-powered vehicles in Delhi-NCR has impacted about 5,000 jobs in the automobile sector and resulted in production loss of around 11,000 units.
SIAM's statement had added, "if extended across the country, it (the ban) would lead to a loss of production of one lakh vehicles over the same period (since December 2015) and would have impacted 47,000 jobs".
According to the Economic Times report, the NGT, on May 24, had said: "The directions passed in regard to NCT (National Capital Territory) would safely be applied to all these cities." However, the green tribunal, according to the report, did concede that there were three major sources of pollution - burning of waste and other materials, dust emission and vehicular pollution.
The report added that before taking a decision the green tribunal wanted the "Central Pollution Control Board to place 'complete and comprehensive' data before it on population density, car density, pollution area and pollution level of major cities across the country".
An earlier report by the pollution control board in response to an NGT order identified key cities where the ambient air quality didn't meet prescribed standards, the report said. Citing a source, the report added that the list had 15 cities - Mumbai, Kolkata, Bengaluru, Patna, Lucknow, Allahabad, Kanpur, Varanasi, Pune, Chennai, Nagpur, Hyderabad, Ludhiana, Jalandhar and Amritsar.
Speaking to the financial daily, the source said: "Of these, air pollution data for 11 cities will be considered in the hearing (on Monday)."
Vishnu Mathur, director general of SIAM, told the Economic Times that "extending the ban countrywide would basically stop production of all large diesel vehicles".
Mathur added, "The polluter-pay principle applies in event of violations. Vehicle manufacturers and oil refineries have been investing to upgrade to higher emission norms and address pollution concerns. Banning vehicles that meet laid down norms is against the fundamental right of companies doing business in the country."
Car makers had been alarmed when, in December last year, the NGT had issued an interim order that new diesel-run vehicles would not be registered in Delhi and that there would be no renewal of registration of such vehicles which are more than 10-year-old.
That same month, the Supreme Court banned the registration of diesel vehicles with an engine capacity of 2,000 cc and above in Delhi-NCR till March 31, 2016, overriding the NGT order.