Heavy overnight rains lashing the metropolis submerged many low-lying localities today even as the weatherman forecast heavy rainfall in the districts of Gangetic West Bengal.

"Heavy to very heavy rainfall will occur at a few places with extremely heavy rainfall at one or two places over the districts of Gangetic West Bengal, including Kolkata," regional MET director G C Debnath said.

He also forecast heavy to very heavy rainfall at one or two places over districts of north Bengal in the next two days.

Till 8.30 am, the city experienced 11 cm rainfall, while Contai in West Midnapore district was the worst-hit recording 26 cm of rains in the same period.

The inclement weather was owing to the south-west monsoon as also a depression over the Bay of Bengal, he said.

City life was thrown out of gear as most arterial roads went under water resulting in huge traffic snarls with vehicles crawling in knee-deep to waist-deep water on important thoroughfares like Central Avenue, Amherst Street, College Street, Park Street, Rabindra Sadan and Southern Avenue.

Students could not make it to their schools and office-goers reached their work places much behind schedule.