Taxi Bachao Committee (Save Taxis committee) president Bimal Guha told IANS that though about 6,800 of the 37,000 taxis that ply in the Kolkata Metropolitan Area come under the ban, '5,800 taxi owners have already applied for replacement.

'But the government has failed to make available the replacement vehicles by talking to Hindustan Motors. So, about 1,000 taxis are not plying,' Guha said.

'The court has not banned two-stroke LPG mode autos. But the government is insisting that only autos with four-stroke engines will be allowed. So, almost the entire fleet of autos is off the roads,' said auto union leader Tapan Agasthi.

Jyotiraditya Guha, a college student, who had to cling dangerously to the footboard of an overcrowded bus Saturday, shuddered to think of the scene from Monday. 'Saturday and Sunday are government holidays. So fewer people are out on roads. The situation will be really bad from Monday. I don't know how I will travel,' he said.

Banerjee had said the withdrawal should be done in phases, noting that one million people comprising the transport operators, workers and their families will be affected by the ban.

'I support the environmental concerns. But the economic condition of these people will also have to considered. Maybe the government can try out using LPG cylinders in these vehicles to meet the emission norms,' he said.

The Calcutta High Court in July 2008 ordered a ban on commercial vehicles registered before Jan 1, 1993 from Kolkata Metropolitan Area, which includes parts of North and South 24-Parganas, Howrah and Hooghly districts.

The ban was originally supposed to come into effect Dec 31, 2008, but was put off till July 31, 2009, following a government plea.