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Chennai floods: Decoding the city’s worst rains in 100 years

With Chennai seeing its worst rainfall in 100 years, we take a look at what caused it, what the impact is, what’s being done and what Chief Minister Jayalalithaa has to do.

December 3, 2015 1:39:12 pm

Why Chennai is seeing its worst floods

While officials at the India Meteorological Department have said the exceptionally strong El Niño, along with a rare “coincidence of various factors”, has resulted in the heavy rain, there’s no denying that Chennai has failed in maintaining an effective storm water drainage system.

In times when the city, and its suburbs, is being pounded with rainfall exceeding normal limits by over three times, a drainage system that isn’t functional, creeks and culverts that are blocked due to excessive dumping of garbage as well as the administration’s failure to ensure timely desilting.

The heaviest rainfall in over a century caused massive flooding across the Indian state of Tamil Nadu, driving thousands from their homes, shutting auto factories and paralysing the airport in Chennai. Reuters The heaviest rainfall in over a century caused massive flooding across the Indian state of Tamil Nadu, driving thousands from their homes, shutting auto factories and paralysing the airport in Chennai. Reuters

Cooum River, Adyar River and Buckingham Canal, which serve as the main rain water drain for the city, have all seen encroachments. In fact, only in September this year, the Madras High Court threatened to summon state’s chief secretary over differences in opinion between the government’s own departments.
Watch Video: Why Is Chennai Under Water? (app users click here)

A PIL was filed by the Kasturba Nagar and Indira Nagar Residents Welfare Forum, seeking the removal of encroachments on the Canal Bank Road along the Buckingham Canal. In their petition, they said the encroachments were not slum dwellings but concrete structures directly affecting the flow of the canal.

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Live updates: The latest from flood-hit Chennai

Had the government acted then, perhaps this area of the city would not have faced such severe flooding.

According to Skymet data, during the month of November, Chennai recorded a whopping 1218.6 mm of rain – three times its monthly rainfall. The normal rainfall figures for November stand at 407.4 mm. On the first day of December itself, Chennai recorded 374 mm and the forecast for the week says heavy rainfall will continue.

Chennai, floods, india, tamil nadu, rains A man carries a girl through a flooded road in Chennai. Reuters

Video: Chennai Rains: Visuals Of People Being Rescued In Boats


Rescue, relief and funding

On November 23, Chief Minister Jayalalithaa had written to Prime Minister Modi seeking Rs 2000 crore as relief fund. However, given the incessant rainfall over the last two days, the AIADMK leader through her MPs in Lok Sabha, urged the Centre to sanction over Rs 8,000 crore from the National Disaster Relief Fund.

Speaking in Lok Sabha, MP A Arunmozhithevan said the calamity should be declared a ‘national disaster’. The Tamil Nadu government requires Rs 2,630.58 crore for temporary restoration and Rs 5,850.34 crore for permanent restoration, he said. Rajya Sabha MPs decided to allocate their MPLAD fund to disaster-hit Chennai.

In terms of rescue and relief operations, the Indian Army, Navy and Air Force are already operating out of Chennai, helping authorities in their efforts. Chief Ministers Arvind Kejriwal and Nitish Kumar have offered their administration’s support. The Karnataka government has offered Rs 5 crore as immediate relief fund.


On Wednesday, the Navy rushed its warship INS Airavat to Chennai. Airavat is carrying 20 divers, and five Gemini boats in addition to four landing craft and two boats that are part of the ship.

Patients being shifted from a flooded hospital after heavy rains in Chennai on Tuesday. PTI Photo Patients being shifted from a flooded hospital after heavy rains in Chennai on Tuesday. PTI Photo

The NDRF and NDMA have pulled in all their resources to help those stranded. “Thirty teams of the NDRF have been sent to Chennai,” Home Minister Rajnath Singh said in Parliament today.

Besides government authorities, NGOs and collectives have come out in large numbers, providing shelter, basic necessities as well as offering manpower in rescue operations. There’s also a website that’s working as a resource centre and assisting those in need of help.

Bharti Airtel, BSNL, Vodanfone, RCom, Aircel and Zomato have come to the rescue, waiving rates and offering free services to their customers. Several IT Parks, located in areas like Taramani, have begun operating as shelters to those rendered homeless.

Economic impact

Chennai hosts over 165 BSE-listed companies (registered in the city) with an aggregate market capitalisation of over Rs 285,000 crore. A big automobile manufacturing and IT hub, the floods have badly derailed the business activity in the city as companies stopped their production activity and shut down offices with instruction for employees to stay home or work from home.


According to Assocham, “the financial loss due to record-breaking rainfall in Chennai and several parts of Tamil Nadu may even exceed Rs 15,000 crore mark as Chennai has come to a virtual standstill and is in the grip of fear and panic.”

The well-established presence of the automobile industry around the city include factories of Hyundai, Ford, BMW, Nissan, TVS, Renault-Nissan and Ashok Leyland, most of which were forced to shut production.


TVS Motor Company, which is based in Chennai, had reported that over the last three weeks, the company suffered sales loss of approximately 15,000 units due to inclement weather.

Auto rickshaws and other vehicles submerged in the flood waters in Kotturpuram area of Chennai. R Senthil Kumar/PTI via AP Auto rickshaws and other vehicles submerged in the flood waters in Kotturpuram area of Chennai. R Senthil Kumar/PTI

Software exporters have invoked Business Continuity Plans, which in tech parlance is an intimation to the company’s other centres across the country to lend a hand to projects handled from Chennai.


Moreover, insurance claims for damage to property, automobiles and other goods following the devastating floods in Tamil Nadu could rise to well over Rs 1,000 crore, general insurance companies estimate.

While the earlier deluge in the state, which started on November 8, has already resulted in claims of around Rs 500-600 crore, the recent torrential rains could cause far more damage, insurers point out. The public sector United India Insurance has the biggest exposure to the state.

What next for Chennai

The first step Chief Minister Jayalalithaa will have to take, once rescue and relief operations are complete, is to set up a task force that reviews all on-going construction activity in the city and its suburbs.

As alarming as it may sound to the real estate industry, given the magnitude of the floods, the Chennai Metropolitan Development Authority must review permissions that have been granted given that it operates as the green channel for commercial constructions in the city and it reviews plans in accordance with the city’s master development plan.

A relook at the land-use in the master plan should also be among the top priorities for CM Jayalalithaa. How much land has been allotted to development projects? Is it commercial or settlement? Is there a need to increase no-go eco-sensitive zones that can serve as catchment areas, specially in low lying areas?

A man carries a dog and wades through a flooded street in Chennai. AP Photo A man carries a dog and wades through a flooded street in Chennai. AP Photo

What is worrying, according to a report submitted by CMDA to the Madras High Court, is that there are over 1.5 lakh illegal structures in the city.

As Arun Janardhan reports from Chennai, despite several HC orders ordering their demolition, the buildings stand — often after appeals to the Supreme Court, and due to the inefficiency of the CMDA’s legal wing. Hundreds of stay orders against demolition orders have been obtained by both business houses and individuals. Across Chennai, illegal construction has been making neighbourhoods unrecognisable — what may have been a tank, lake, canal or river 20 years ago, is today the site of multi-storey residential and industrial structures, he says.

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Our Take: After The Deluge

The heavy rain has exposed the creaking public infrastructure in Chennai — like the 2005 deluge did in Mumbai or the 2014 floods in Srinagar. One of the largest manufacturing and commercial hubs in the country, Chennai, understandably, has been expanding at a fast pace. From heavy industries like automobiles and auto components to software, BPOs, education and healthcare, the city has built a wide economic base and is home to a cosmopolitan workforce. Yet, the administration has been slow to augment the infrastructure to take the extra load of people and vehicles.

In Chennai and elsewhere, the approach to urban governance needs to change. Mundane aspects of city administration like building and maintaining water, drainage and sewage systems, mass transport facilities, etc are ignored as the conversation shifts to concepts like smart cities. Civic bodies need massive infusions of funds, skills and technologies if cities are to become liveable urban spaces. That’s the lesson from the Chennai deluge. Read more here.

chennai, rains, monsoons, chennai floods, imd graph