Many parts of Calcutta were left waterlogged after heavy rain on Tuesday afternoon while some other parts were hardly drenched.

A Met official attributed the contrast to the difference in the nature of clouds over different parts of the city.

The Met office recorded 15mm of rain in Alipore, which serves as the official recordkeeper for Calcutta, between 8.30am and 8.30pm on Tuesday. A bulk of it happened between noon and 3pm.

Figures obtained from the pumping stations of the Kolkata Municipal Corporation painted a picture of contrast.

Thanthania got 98mm between noon and 3pm. During the same period, Dutta
Bagan (in Paikpara) and Maniktala got 85mm each, Ultadanga got 84mm, Belgachhia got 76mm and Palmer Bazar 40mm. Ballygunge got 5mm, Mominpore got 15mm and Behala got 10mm.

In Met parlance, 60mm of rain in 24 hours is considered heavy.

“Parts of north Calcutta and North 24-Parganas got more rain than the remaining
areas. The thunderclouds over these areas were taller and had much more moisture content than their counterparts over south Calcutta,” said a Met official.

Several parts of north Calcutta were waterlogged.

Around 2pm, College Street and Surya Sen Street were under ankle-deep water. Shyambazar bylanes like Brindaban Pal Lane and Santi Ghosh Street were also submerged under water. A long stretch of Bagmari Lane between Kankurgachhi and Girish Park was also waterlogged, forcing autos between the two pockets to take a detour.

The rain hit traffic on several thoroughfares. A Gariahat resident took an hour to reach the BBD Bag area on an app cab, spending half of the time crossing Lansdowne.

A system over Bangladesh was behind the showers, said the Met office.

“The low pressure area over south Bangladesh and neighbourhood now lies over central parts of Bangladesh and neighbourhood at 8.30am on Tuesday,” said a Met bulletin.

“It is likely to move north-northwestwards across West Bengal during the next 48 hours. The monsoon trough at mean sea level now passes through Sri Ganganagar, Rohtak, Orai, Churk, Malda to the centre of the low pressure area over central parts of Bangladesh and neighbourhood,” the bulletin said.

The system was moving north and was over north Bangladesh on Tuesday night, the Met official said.

“Tripura and neighbouring areas are also getting rain because of the system, which is losing strength now,” he added.

Rain is not ruled out in Calcutta and neighbouring areas on Wednesday and Friday. “But the intensity is likely to go down,” the official added.