Cyclonic Storm Nilam (IMD designation: BOB 02, JTWC designation: 02B, also known as Cyclone Nilam) was the worst tropical cyclone to directly affect south India since Cyclone Jal in 2010. Originating from an area of low pressure over the Bay of Bengal on October 28, the system began as a weak depression 550 km (340 mi) east-northeast of Trincomalee, Sri Lanka. Over the following few days, the depression gradually intensified into a deep depression, and subsequently a Cyclonic Storm by October 30. It made landfall near Mahabalipuram on October 31 as a strong Cyclonic Storm with peak winds of 85 km/h (50 mph).
In Chennai’s Marina Beach, strong winds pushed piles of sand ashore and seawater reached nearly 100 meters inland. Schools and Colleges in the city remained closed for more than three days. More than 3000 people were evacuated around Mahabalipuram in the wake of the storm. Schools and colleges in Chennai declared holidays until 1 November as 282 schools had been converted into relief centers. Government offices and private organizations closed their operations by 3 pm to ease traffic congestion. Cyclone shelters had been arranged in Nagapattinam and Cuddalore districts.
Mahabalipuram faced power outages and 90 trees were uprooted and two huts were damaged. While damages to property were considerable, human casualties were very few. Nilam was initially estimated to have caused economic losses of around 700 million (US$12. 74 million) to 800 million (US$14. 56 million). The figures soon went up to 100 crores (US$18. 2 million). Later, as the Andhra Pradesh government conducted their review on the storm, it was revealed that the state suffered huge economic losses of 200 crores (US$36. 4 million).