<span style="color: #222222;">In our series 'Expert Speak' on All India Radio, we bring you the views of the leading medical experts on COVID-19.<br />'' <br />'' Talking to AIR News, Senior Physician from Saftarjung Hospital, New Delhi Dr. M.K. Sen said, these are the testing times. He said, the basic rules should be followed even during Lockdown 4.0.</span><br />''  <br />