Delhi records highest single-day July rain since ’82

New Delhi, July 9

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Delhi recorded 153 mm of rain in 24 hours ending 8:30 am on Sunday, the highest in a single day in July since 1982, the India Meteorological Department said.

An interaction between a western disturbance and monsoonal winds is leading to an intense rainfall spell over northwest India, including Delhi which experienced the season’s first “very heavy” rainfall.

The Safdarjung Observatory, the city’s primary weather station, recorded 153 mm of rainfall in 24 hours ending 8:30 am on Sunday, the highest since the 24-hour rainfall of 169.9 mm on July 25, 1982, a senior IMD official said.

It was the third-highest single-day rainfall for July since 1958, it added.

The city logged 133.4 mm of rain on July 10, 2003, 126 mm on July 28, 2009, and 125.7 mm on July 8, 1993. The all-time high of 266.2 mm on July 21, 1958.

Delhi has recorded eight “very heavy” rain events (between 115.6 mm and 204.4 mm) in July since 1969, the IMD data shows.

The Met Office has issued a yellow alert, warning of moderate rain which could cause more problems to the residents of Delhi.

The weather stations at Ridge, Lodhi Road and Delhi University recorded 134.5 mm, 123.4 mm and 118 mm of precipitation, respectively.

According to the Met Office, rainfall below 15 mm is considered “light”, 15 mm to 64.5 mm is “moderate”, 64.5 mm to 115.5 mm is “heavy”, and 115.6 mm to 204.4 mm is “very heavy”.

Any amount exceeding 204.4 mm is classified as “extremely heavy” rainfall.

The heavy rain submerged parks, underpasses, markets and even hospital premises, and caused chaos on the roads.

Pictures and videos of commuters wading through knee-deep water flooded social media platforms, raising concerns about the efficiency of the city’s drainage infrastructure.

Strong winds and showers also caused disruptions in power and internet connectivity in several areas.

With the showers bringing back the familiar scenes of waterlogged roads and long lines of vehicles stuck in the deluge, residents expressed anguish over Delhi’s “poor drainage system”.

Delhi has three major drainage basins: Najafgarh, Barapullah and Trans-Yamuna.

During rainfall, stormwater on the eastern side of the central ridge directly flows into the Yamuna. On the western side, smaller drains merge into the Najafgarh drain, which eventually empties into the river.

The eastern region of Delhi is low-lying and was originally part of the Yamuna floodplain. The existing stormwater drainage system in Delhi is prone to congestion, primarily caused by waste and sewage, leading to sluggish water flow.