Has Chennai taken the bite out of the mosquito?

Going by the official claim, intensive fogging and spraying operations by the Chennai Corporation have reduced the mosquito density in the city from 80 to the sub-40 level per ten man-hours. Not everyone buys it.

CAN THEY BREED HERE? Corporation workers spray insecticide in a bid to prevent mosquito breeding in the polluted Cooum river at Sivananda Salai on Monday. Photo: R. Ragu

Following intensive fogging and spraying operations by the Chennai Corporation, the mosquito density in the city has come down from 80 to the sub-40 level per ten man-hours.

An official of the Corporation’s Health Department said that mosquito density was arrived at by dividing the total number of mosquitoes caught by the number of minutes taken to catch them. The result so obtained is multiplied by 600 minutes (10 man-hours).

The mosquitoes are caught using suction tubes. The official added that if the density was below 50 it was considered low, between 50 and 83 medium and 84 and beyond, high.

According to data provided by the civic body, in Tondiarpet, Stanley Nagar in Washermenpet and M.G.R. Nagar and Kutcheri Road in Mylapore the density was 80 during a survey on September 12 and 13. In Anna Nagar it was 72, Spurtank Road 48, G.N. Chetty Road 64 and Lloyds Road 72.

A similar survey on September 19 and 20 found that the density had come down to sub-40 levels in all areas except Anna Nagar, where it was 48.

Corporation Health Officer P. Kuganantham said, “The civic body started fogging and spraying operations on August 31. We are concentrating on the breeding and resting places of mosquitoes. Anti-larvicide is being sprayed in canals, slum areas, parks and stormwater drain networks in the mornings and these areas are fogged in the evenings.”

Mayor M. Subramanian said that unlike in the past, this year, the civic body was conducting intensive fogging and spraying operations. “We are also undertaking de-silting operations in canals to prevent breeding of mosquitoes.”

Residents of several localities, however, say there is little change in the situation. Krishnamurthi, a resident of Abhiramapuram, said, “We did not see any fogging or spraying operation taking place in our area.”

Annathurai of Moolakothalam said his locality, located between a garbage dump and a graveyard and the Cooum river in the neighbourhood, was infested with mosquitoes. “Though the Corporation undertakes regular fogging operations, it is of little use.”