Twenty people were tested positive for Covid-19 in the state on Sunday, out of which five each are in Chennai and Chengalpattu. The state had been reporting less than 10 cases for the past few months.As many as 391 people were tested on Sunday and the Test Positivity Rate (TPR) was 6.2%. The operational guidelines for the disease have been revised in the view of surge in Covid-19 cases in Thailand, Indonesia, and the neighbouring state of Kerala.