<span style="color: #222222;">Delhi Chief Minister Arvind Kejriwal today said highest number of 21 thousand 144 Covid tests were conducted in a single day in the national capital yesterday. </span><br />'' <br />'' <span style="color: #222222;">In a tweet, Mr Kejriwal said city government has increased testing by 4 times. He said Delhi is now following strategy of very aggressive testing and isolation.</span><br />''