New Delhi, Dec 30 : The Centre on Thursday wrote letters to eight states and union territories (UTs) over the rise in number of new Covid cases. The letter has been addressed to those states reporting increased numbers of Covid and Omicron variant cases. The letter has been written to the health secretaries of Haryana, Delhi, Gujarat, Jharkhand, Karnataka, West Bengal, Tamil Nadu and Maharashtra. Union Health Secretary Rajesh Bhushan directed these states to take measures as there has been an increase in Covid cases and lessening of doubling time. These states have been told to enhance testing, strengthen hospital-level preparedness, increase pace and coverage of vaccination. The Center has also directed the states to enhance the testing in a focused manner with maintaining the ratio between RT-PCR and Rapid Antigen Test (RAT). The states have been advised to go for proactive contact tracing and isolation and quarantine of the contacts of positive cases, their testing and follow up. The states have also been told to speed up the Covid vaccination coverage along with enforcing the Covid Appreciate Behaviour. Meanwhile, India on Thursday registered 13,154 fresh Covid cases and 268 deaths in a span of 24 hours. With the addition of the new deaths, the total death toll reached 4,80,860. The Omicron infection tally has also climbed to 961 across the nation. However, out of total Omicron positive, 320 have been discharged from hospitals. So far 22 states have reported Omicron cases, said the Union health ministry. /IANS