Plumes of poisonous insecticides can be seen wafting through Delhi streets these days as the municipal corporations ramp up fogging with dengue cases on the rise.
But, officials of the health departments as well as leaders of the corporations admit that fumigation is not effective in preventing dengue, and is being done, in part, to placate the public. The civic bodies do not have a regular fumigation programme, and only start it when dengue cases start increasing during the monsoon.
For instance, the North Delhi Municipal Corporation did not carry out any fumigation last year as the cases of the vector-borne disease were not too high.
“This year, we started the fumigation on September 1. We carry out outdoor fogging in the entire area and indoor fumigation is done in and around the places where cases have been reported,” said North Corporation’s municipal health officer (MHO) A.K. Bansal.
The programme is based on the Central government guidelines and maintains a balance between efficacy and safety as the insecticides used have some side-effects on humans. In its budget for 2015-2016, the South Delhi Municipal Corporation (SDMC) has set aside Rs. 10 crore for its dengue and malaria programme.
North Delhi Mayor Ravinder Gupta said the fumigation programme had been intensified in areas where more cases were found. N. K. Yadav, the South Corporation’s MHO, said fumigation was not a preventive measure. “Fogging kills adult mosquitoes. It has no effect on larvae so it cannot prevent dengue. However, it is used for interrupting transmission. We have started fumigation now, and will do it twice a day in areas where more cases have been found,” said Dr. Yadav.
SDMC Standing Committee chairperson Radhey Shyam Sharma admitted that fumigation was not very effective when done in the open. “We do it as residents create pressure. They create a panic when dengue cases are reported. Fumigation is only effective indoors, that too when the doors and windows are kept shut for some time,” said Mr. Sharma. The East Delhi Municipal Corporation (EDMC), which started fumigation at the beginning of this month, has seen the least number of dengue cases. EDMC Mayor Harshdeep Malhotra said this was because the civic body had deployed four people in each of its 64 wards to spray larvacide and conduct fogging. “We had taken preventive measures well in advance by spraying larvacides wherever mosquito breeding was found,” said Mr. Malhotra.