New Delhi, July 31 - The Supreme Court Friday refused to suspend a Calcutta High Court order, directing the phasing out of all commercial vehicles older than 15 years from the metropolis to check pollution.

A bench of Chief Justice K.G. Balakrishnan and Justice P. Sathasivam refused to stay the July 2008 verdict of the high court saying it would hear the matter Tuesday.

The high court had ordered the West Bengal government to phase out 15-year-old commercial vehicles from the municipal limits of Kolkata within a year.

The deadline ends Thursday and city transporters, who oppose the order, have called for a strike from Saturday.

In a last ditch effort, the transporters have come to the apex court to challenge the high court ruling, but the apex court deferred the hearing to next week.

Kolkata has 6,500-odd buses and mini-buses, out of which around 2,830 are more than 15 years old.