The order also prevented the state government from registering new diesel vehicles of 2000 cc and above, except those in the public transport and government sector.

The bench, comprising Justice Swatanter Kumar and member Bikram Singh Sajwan, was acting on a petition from the Lawyers Environmental Awareness Forum. The order came on the inaugural day of the circuit bench in Kochi.

Kerala Transport Commissioner Tomin J Thachankery said the government was not heard by the tribunal bench. At least 2 lakh vehicles will have to be taken off the roads in a month if the order is implemented, he said, adding “We will move the high court against the order.”

As per the order, all diesel vehicles in the category of light and heavy vehicle which are aged more than 10 years will not be allowed to ply in Thiruvananthapuram, Kollam, Kochi, Thrissur, Kozhikode and Kannur — the six municipal corporations in Kerala. After one month, vehicles found violating the order will be fined Rs 5,000 as environmental compensation. The traffic police or state pollution control board will be assigned to collect the amount, which will be used to clean up the environment in those cities. Thachankery said that if the verdict is implemented, 4,000 of the 16,000 privately owned passenger buses would be affected. The cash-strapped state transport corporation has around 2,000 diesel buses in its 5,500-odd fleet, which are more than 10 years old. The directive against registration of new diesel vehicles will also impact the sale of SUVs and MUVs in Kerala, a booming automobile market in the country. Road safety expert Upendra Narayan said the state is ill-prepared to implement the order in one go. The social and economic implications should have been taken into consideration, he said, adding that restrictions in the long term could be welcome.