The Covid-19 test positivity rate in nine out of 23 districts of West Bengal was more than 10% last week, a survey conducted by the state health department showed, PTI reported on Tuesday. The survey noted that the test positivity rate in some areas even crossed 20%.

In the previous round of survey carried out in mid-June, the test positivity rate in West Bengal was not more than 3% in any of the districts, The Times of India reported.

For the survey conducted last week, 400 samples were collected from every hospital across 23 districts of the state.

“Murshidabad is the only district where the positivity rate is below 1%,” an official of the health department said.

Out of all the districts surveyed by the department, Nandigram had the highest test positivity rate of 24.6%. In North 24 Parganas the rate was 23.75%, followed by Darjeeling at 19.10%. Uttar Dinajpur ranked fourth with a test positivity rate of 16.25%.

Kolkata’s test positivity rate surged to 13.13% from last month’s 0.9%, reported The Times of India.

“The infection spread starts from the city and then goes to the districts,” a state health official told The Times of India. “Since eight districts are showing higher positivity rate than Kolkata, we should witness a decline soon.”

Diptendra Sarkar, a member of the Covid-19 task force at the Institute of Post Graduate Medical Education And Research in Kolkata, said that the surge in cases had already hit a peak. The number is expected to plateau for about seven to 10 days after which there will be a steady decline, he added.

“We should not be worried about the asymptomatic or the mild cases,” he added. “Focus should be on the high-risk patients as we might see higher fatality a week after the peak.”

On Monday, West Bengal recorded 1,915 new Covid-19 cases with the daily positivity rate of 21.29%, an official bulletin said. Three new deaths were reported in the state and 967 patients had recovered in a day. The recovery rate of the state is currently at 97.79%.