In November when the city was lashed by torrential monsoon rains, one part of Mangadu village – Selvavinayagapuram, Hari Avenue, Om Shakthi Nagar, Appavu Nagar, Srinivasa Nagar and Janani Nagar – was marooned. Officials said this was because the floodwater could not drain due to more than 250 encroachments, including both houses and commercial buildings, that were built on the Thanthikal channel of Chembarambakkam reservoir. The channel drains the excess water from Mangadu village, Nazarathpet, Kumananchavadi and Iyyappanthangal areas to the Porur tank, from where it would reach Adyar river.