Overnight heavy torrential rains left Kolkata and the surrounding areas submerged Tuesday, paralysing the day-to-day activities just days ahead of Durga Puja.

Here’s 5 key things to know about the rain fury and its impact

The city received 251.4 mm of rainfall in less than 24 hours, the highest since 1986 and the sixth-highest single-day rainfall in the last 137 years, only behind the record 369.6 mm in 1978, 253 mm in 1888, and 259.5, 98 years later. With the southern and eastern neighbourhoods like Garia Kamdahari (332 mm) and Jodhpur Park (285 mm) worst hit, while Thantania in north Kolkata received 195 mm of rain.

At least 10 people, including nine from electrocution, died as Kolkata witnessed its heaviest rain in nearly four decades, paralysing the city and adjoining districts Tuesday. Across the city, arterial roads such as EM Bypass, AJC Bose Road and Central Avenue turned into rivers, while traffic crawled for hours at key intersections like Park Circus, Gariahat, Behala and College Street.

West Bengal Chief Minister Mamata Banerjee called the downpour “unprecedented”, however, blaming poor dredging of the Farakka barrage and lapses by private power utility CESC for the deaths, while appealing to people to stay indoors. CESC supplies electricity in Kolkata and adjoining areas, and not the state government, she said later in her address, adding: “It is their duty to ensure people do not suffer because of this. They will do business here, but will not they modernise? They should send people to the field and fix this.”

Following the heavy showers, the West Bengal Education Department announced that the month-long Durga Puja holidays in government-run and aided schools, colleges and other educational institutions in the state will begin on Wednesday, two days ahead of the schedule, in view of the heavy rainfall in the state. Meanwhile, Calcutta University (CU) and Jadavpur University (JU) suspended all academic activities and examinations for the day.

Train services have been partially affected to and from the Howrah and Kolkata terminal stations of Eastern Railway, as the tracks have become waterlogged due to heavy rainfall. Meanwhile, significant waterlogging was reported in the mid-section of the Blue Line (Dakshineswar–Shahid Khudiram), particularly between Mahanayak Uttam Kumar and Rabindra Sarobar stations, prompting the immediate suspension of services on this stretch. Air travel was also hit hard. At least 90 flights were cancelled and over 90 others delayed from the NSC Bose International Airport till evening.