In the list of 20 COVID-ravaged districts in India, six belong to Kerala.
Ernakulam is seventh while Kozhikode is ninth in the list prepared by the Centre in an effort to devise measures to curb COVID spread.
The other four are Malappuram, Thrissur, Thiruvananthapuram and Palakkad.
The Centre has directed the States and Union Territories to ramp up testing.
Kerala reported 41,971 new COVID cases on Saturday.
The test positivity rate here has surged to 28.25.
Sixty-four COVID deaths were also confirmed in the state.