Tamil Nadu on Sunday reported a new single day high of 4,979 fresh Covid-19 cases as the overall tally crossed 170,000 while 78 fatalities propelled the death count to 2,481. As many as 52,993 Covid samples were tested, the highest so far in a day, and the cumulative tests so far touched 19,32,492, a health department bulletin said. Greater Chennai Corporation Commissioner G Prakash said the city civic body was the first in the country to have conducted 500,000 RT-PCR tests. Till July 18 from March, 500,000 tests were conducted, he said adding sample testing has been increased to 13,000 per day from about 4,500 (in recent times) in the Corporation areas. Of the dead were two men aged 22 and 37 and two 38- year old women and in total 75 had co-morbidities and 2,481 people have so far succumbed to the virus in Tamil Nadu.