In an order issued on Friday, the Tamil Nadu Health Department has made wearing of masks mandatory in the state and violators will have to pay Rs 500 as fine.
The Department said the decision was taken considering the rising cases of Covid-19 in the country, especially in Delhi,.
Tamil Nadu has also witnessed a slight increase in fresh cases in the past couple of days.
The Department had earlier withdrawn the mask mandate following a decline in the number of infections.
On Thursday, 39 people tested positive for Covid in Tamil Nadu, with 31 registered the previous day.
Twelve students of IIT Madras had also tested positive for the virus and the premium institute was declared a Covid zone on Thursday.
The students were however not admitted to hospital even though they had taken first aid care from the Guindy government hospital.
Sources in IIT Madras told IANS that while they were ready to admit the students at Guindy Government hospital, doctors have informed them that the students do not require hospital administration.