The thundershowers on Monday evening that brought relief from the scorching conditions also bared, for the umpteenth time, the lack of civic preparedness in Calcutta.

Several pockets of the city remained waterlogged hours after it had stopped raining.

A stretch of the service road along EM Bypass, between the Ruby and VIP Bazaar, was flooded even on Tuesday afternoon, more than 16 hours after the showers had subsided.

“There is a block in the sewer line that carries the sewage and rainwater from that stretch of the service road because a culvert is being built over a canal. This is the reason why water is draining out very slowly from that stretch,” said an official of the Kolkata Municipal Corporation (KMC).

The Alipore Met office recorded around 70mm of rain between 8.30pm on Monday and 8.30am on Tuesday. But the bulk of it was recorded for a couple of hours from 7pm. In Met parlance, 60mm of rain in 24 hours qualifies as heavy. The volume of rain was the maximum the city witnessed in a long time.

But the flooded roads also point to sewer lines that are not regularly desilted and clogged gully pits.

A man returning home at 10pm on Monday said stretches of the pavement along Rashbehari Avenue were flooded, forcing pedestrians to walk through the road. “The gully pits were partially blocked in some places, which was why these pockets were flooded,” said the man.

Kasba’s BB Chatterjee Road or Jadavpur’s Ibrahimpur Road remained flooded till past Monday midnight.

“I had to wade into the dirty water to reach home,” said a Jadavpur resident who returned from her workplace in central Calcutta past 10.15pm.

The gully pits, located along the edges of roads, let water flow into the gully, from where it passes into the main underground sewer lines.

Regular cleaning of the pits can spare the trouble, more so before the forecast of rain. The Met office had issued a thunderstorm warning for south Bengal, including Calcutta, at least two days in advance.

Single-use plastic is the biggest choker of the gully pits.

“We clean gully pits through the year. Monday’s rain was so heavy that some waterlogging was bound to happen,” said a KMC official.

A giant billboard opposite the ITC Royal Bengal fell on an adjoining Metro Railway premises. The pole that the scaffolding stood on was uprooted.

This newspaper reported on Sunday about the threats from run-down hoardings, many of which have rusted and their tin plates keep fluttering in the wind.

About 10 electric poles fell or were damaged across the city, said a senior engineer of the KMC.

In some places, the poles broke from the middle. “We have to replace the poles,” said the engineer, adding that thick bunches of cables tied to the poles brought them down in some places. In a few other places, the poles were damaged after large tree branches fell on them.

The owner of a roadside tea stall was electrocuted after he is said to have come in contact with a live wire attached to a signboard on Strand Road on Monday morning, hours before the rain.

The sky switched between being sunny and cloudy on Tuesday.

“Because of the favourable synoptic conditions and strong moisture incursion from Bay of Bengal, thunderstorm with lightning along with gusty wind speed and thunder squall activity is very likely to continue over the districts of West Bengal,” read a Met bulletin issued on Tuesday.

The showers dragged the Celsius down significantly. The minimum temperature on Tuesday was 21.7 degrees, five notches below normal. The city last witnessed a lower minimum temperature 45 days ago, on March 22, when the Celsius dropped to 20 degrees.