Just as Calcuttans thought the tryst with Cyclone Dana was past, it was hit by a fresh spell of formidable rain on Friday evening.

By 8pm, Thanthania, MG Road, Bidhan Sarani and the Patipukur underpass in the north and Elgin Road, Hospital Road, Sarat Bose Road, Camac Street and the intersection of Loudon Street and Park Street in the south were flooded.

Many of these roads, and some more, were already flooded by the incessant rain between early morning and afternoon. The Kolkata Municipal Corporation managed to drain water out of several pockets by the evening. But the fresh spell put a spanner in their efforts.

“The efforts of the workers from the conservancy, drainage and other departments bore fruit in several areas. Low-lying areas like Bidhan Sarani, College Street and Thanthania have been infamous for waterloggingsince before my birth. Areas that would earlier remainwaterlogged for two to three days are now cleared within hours, provided the rain stops,” said Firhad Hakim, Calcutta’s mayor.

“We are helpless if it continues to rain. Friday’s rain was unusually heavy,” Hakim said.

According to the readings at the drainage pumping stations of the Kolkata Municipal Corporation, Jodhpur Park received 190mm of rain between 4am and 8pm on Friday. Ballygunge got 152mm and Kalighat 127mm of rain during the same period.

Many other places in Calcutta received well over 100mm in this period.

In Met parlance, 60mm in 24 hours qualifies as heavy rain. Calcutta’s drainage infrastructure is only capable of handling up to 6mm of rain in an hour, officials of the civic body said.

By noon on Friday, Park Street was under almost knee-deep water. Around 1pm, the waves created by passing cars toppled a couple of two-wheelers parked near the Starbucks outlet on the ground floor of Park Mansions on Park Street.

Minutes later, two policemen were seen pushing a car that stuttered to a stop at the intersection of Park Street and Camac Street.

Adjoining Camac Street, Theatre Road, Loudon Street and Lower Rawdon Street wore a similar picture.

College Street looked like a stream around the same time. The entrance to Calcutta University and the portico of Presidency University were flooded.

In New Town, several housing complexes, including Uniworld City, Rosedale housing complex and DLF Elita Garden Vista had to operate bilge pumps to drain out water from their basement parking lots.

“We had to operate our pumps inside the basement car parking areas to ensure they did not get inundated as it rained throughout the day,” said Ranjan Basu, the president of the residents’ welfare association of Rosedale housing complex.

At the Ruby crossing, the road leading to Urbana had ankle- to knee-deep water and workers were seen removing manhole covers to drain out the water faster.

Civic officials said the heavy rain coincided with high tide in the Hooghly. “There was high tide from 6.43am to 2.47pm. The sluice gates of the Hooghly were shut at a time the rain was most intense. It only added to the waterlogging,” said an official in the drainage department of the KMC.

The pumping stations drain water from roads into various canals such as Begor Khal, Charial Khal, Monikhali, Suburban Head-cut Canal, Town Head-cut Canal and the Tollygunge-Panchannagram channel.

As the high tide ended and these pumping stations swung into action, another sharp spell of rain started.

Earlier in the day, even the hospitals were flooded. The cardiology building and Ronald Ross building at SSKM Hospital had more than ankle-deep water around 11.30am.

Patients’ relatives were seen pushing trolleys through the water.

The entrance to National Medical College and Hospital was also flooded. The blood bank and physical medicine department had ankle-deep water.

Many people remained indoors on Friday.

The spell of rain in the evening slowed traffic and snarls formed on key roads such as EM Bypass, Central Avenue, AJC Bose Road and APC Road.