'We have no problems with a day's token strike. But if they go for an indefinite strike, then commuters will be inconvenienced,' he said.

Meanwhile, ruling Left Front major Communist Party of India-Marxist (CPI-M)'s labour arm Centre of Indian Trade Unions (CITU) demanded the striking operators pay the day's wages to the drivers and other workers.

The labour union warned the protestors that if the strike is stretched beyond Friday, then the workers would forcibly take out vehicles on the roads from Saturday.

The Calcutta High Court July 2008 ordered a ban on commercial vehicles registered before Jan 1, 1993, from Kolkata and its outskirts. It said the order should be implemented by Dec 31, 2008, in the Kolkata Metropolitan Area (KMA), which includes parts of North and South 24-Parganas, Howrah and Hooghly districts.

Later, the date for imposing the ban was put off till July 31, 2009, following a state government plea.

The state government decided to phase out old vehicles from July 25 to implement the court order.