The cyclone was crossing the coast South of Chennai as observed at 4 pm, a bulletin issued by the Area Cyclone Warning Centre here said. The system would take two hours to cross the coast and then move further northwards before weakening gradually, it said.
About 4,000 people residing close to the coast in Mahabalipuram, a famous tourist spot known for its shore temples and sculptures, have been evacuated to safer places, officials said.
People in the affected areas have been advised to remain indoors till tonight while state government employees were asked to leave for their homes at 3 pm. A holiday has been announced for educational institutions in coastal districts for tomorrow.
Chennai is experiencing strong wind though the intensity of rain is less and power supply has been disconnected in many of its parts as a precautionary measure.
Under the influence of the cyclone, rainfall will occur in most areas with heavy to very heavy falls at isolated places over North interior Tamil Nadu during the next 12 hours.
Rainfall at many places with isolated heavy to very heavy falls would also occur over North coastal Tamil Nadu during the same period, the Met department said.
Meanwhile, Southern Railways announced diversion and partial cancellation of trains, especially those passing through coastal districts. Trains were also being operated on low speed to ensure safety, officials said.
In Chennai, about 100 trees were uprooted due to the gusty winds. Traffic movement was slow as motorists, including those driving four-wheelers faced difficulty due to strong winds. The incessant rain damaged crops in Cauvery delta region, farmers said.
Also, heavy rains and gale continued to lash Nellore and other districts of Andhra Pradesh close to Tamil Nadu today due to the cyclonic storm 'Nilam.'
There were no reports of death or damage to property till evening, the state Commissioner for Disaster Management said.
The cyclone was expected to cause minor damage to power and communication lines, and also to the standing rice and groundnut crops. The government has set up control rooms at the Secretariat here and at the district and division level. Senior IAS cadres have been posted in 13 coastal mandals as special officers and teams have been kept ready for evacuation in low-lying areas, the Commissioner said.