Cyclone Gaja centred over Bay of Bengal is likely to intensify into a severe cyclonic storm and cross Tamil Nadu coast between Pamban and Cuddalore in the next 12 hours on Thursday, the India Meteorological Department (IMD) said.
The wind speed would be touching 80-90 kmph gusting to 100 kmph, the IMD added.
In its Thursday bulletin, the IMD said, the cyclonic storm moved at 14 kmph and lay centred over east-northeast of Nagapattinam of Tamil Nadu at 5:30 am and it is likely to move west-southwestwards and cross between Pamban and Cuddalore.
Schools and colleges have been closed in Tiruvarur, Thanjavur, Nagapattinam, Ramanathapuram and Pudukottai districts in Tamil Nadu and in Karaikal district in Puducherry.
Anna University has cancelled all its examination scheduled for Thursday amid cyclone warnings from IMD.
In Tamil Nadu, teams of National Disaster Response Force (NDRF) were on stand by.
Several relief centres have been established in view of the cyclone.
