Kolkata, Sep 23 : Torrential overnight rain left Kolkata paralysed on Tuesday, killing at least seven people due to electrocution and bringing life in the metropolis to a grinding halt as large swathes were submerged, transport services crippled, and traffic movement thrown out of gear. According to IMD data, with an average of 251.4 mm overnight downpour, this was the third-highest September month rainfall, which battered the city in nearly half a century, with some pockets receiving as high as 332 mm of rains in just a few hours. The relentless downpour caused massive flooding across the city, leaving thousands of commuters stranded and severely affecting transport services across roads, railways and flights.

Chief Minister Mamata Banerjee described the downpour as "unprecedented", lashing out at poor dredging of the Farakka barrage and lapses by private power utility CESC, while appealing to people to stay indoors for their own safety. "I have never seen rain like this. I feel so bad for the people who have lost their lives in the cloudburst. I heard 7–8 people have died due to electrocution by open or unattended wires. It is so unfortunate… Their families must all be given jobs by the CESC. I am saying this clearly. We will also do whatever is possible to help," Banerjee told a Bengali news channel. According to the IMD, the 251.4 mm average rainfall throughout early Tuesday morning in Kolkata was bettered by 369.6 mm showers on September 28, 1978 and 259.5 mm rains on September 26, 1986.

Records for all months maintained by the Met office show that only on five occasions in the last 140 years did Kolkata experience rains in higher volume than what it received on Tuesday. The heavy overnight rains brought Kolkata to its knees on Tuesday as the city was preparing for its biggest festival, Durga Puja, which will begin later this week. The intensity of the downpour was higher in the southern and eastern parts of Kolkata, the KMC said. Garia Kamdahari recorded 332 mm of rainfall in just a few hours, followed by Jodhpur Park (285 mm), Kalighat (280 mm), Topsia (275 mm) and Ballygunge (264 mm). Thantania in north Kolkata received 195 mm.

Squarely blaming the utility, Banerjee said, "Electricity is supplied by CESC, not us. It is their duty to ensure people do not suffer because of this. They will do business here, but not modernise here? They should send people to the field and fix this." "Even our houses are submerged; we are all suffering. I am feeling so bad for the Pujo pandals as well. Schools have been asked to declare holidays and office-goers advised to stay home today and tomorrow," the chief minister said, adding she was in constant touch with the Mayor, chief secretary and police.

Those who lost their lives include Firoz Ali Khan (50) of Beniapukur, Pranatosh Kundu (62) of Netaji Nagar, and Mumtaz Bibi (70) of Ekbalpur, besides an unidentified person in Gariahat. Kolkata Mayor and state Urban Development Minister Firhad Hakim said, "So far, we have received information of four deaths due to electrocution in different places in the city, but later official tallies placed the figure at seven. Hakim said that most parts of the city were waterlogged and teams of the Kolkata Municipal Corporation (KMC) were working round the clock to drain out water. "We fear that the high tide which is around 1.30 PM today, may not help in our efforts to drain out the excessive water. It would be around 10 PM when the situation could be expected to improve," Hakim said.

Across the city, vehicles lay stranded on arterial roads, commuters waded through waist-deep water at several intersections, and Metro services were suspended on a long stretch of the Blue Line. Traffic movement was severely affected at key intersections such as Park Circus, Gariahat, Behala and College Street, while long snarls were reported on EM Bypass, AJC Bose Road and Central Avenue. Several smaller lanes in south and central Kolkata were completely cut off. Commuters complained of buses breaking down mid-way, while taxis and app cabs either stayed off the roads or charged exorbitant fares. Many schools declared a holiday as students and staff could not make their way through flooded streets. Calcutta University and Jadavpur University also suspended all academic activities for the day.

Office-goers faced severe hardships due to lack of public transport and traffic snarls. Train and Metro Railway services were badly hit. A Metro spokesperson said services were suspended between Shahid Khudiram and Maidan stations since morning hours. "Truncated services are being run between Dakshineswar and Maidan stations," the official said, adding that normal services were expected to resume soon. The rains disrupted air travel, leading to the cancellation of at least 30 flights and significant delays in 31 others, officials said.

At Kolkata's Netaji Subhas Chandra Bose International Airport, multiple flights were grounded due to adverse weather conditions, with authorities citing incessant rains and restricted visibility as key safety concerns. Trains to and from Howrah and Kolkata terminal stations were partially affected, while Circular Railway services were suspended due to waterlogging at Chitpur yard. The IMD said a low-pressure area over the northeast Bay of Bengal was likely to bring more heavy rain in several south Bengal districts.