The state capital’s civic body plans to procure four more cold mist fogging machines by April to add to its mosquito-fighting arsenal.

The Ranchi Municipal Corporation (RMC), has three such machines.

In cold mist fogging the insecticide solution is mechanically broken down using high-speed rotary nozzles to produce an aerosol. The cold-mist fogging technique is believed to be effective against mosquitoes as the chemical is mixed with water and sprayed with pin-point accuracy at identified adult-mosquito resting places like underneath drains, gardens pots and interiors of houses, and the chemical lasts for a long time.

“Chemicals used in cold-mist fogging technique efficiency last for more than a week as compared to thermal fogging,” RMC commissioner Manoj Kumar said.

A larvae takes nine days to develop into an adult Aedes aegypti mosquito, the species that carries the dengue virus. Ranchi has seen outbreaks of the disease for the last few years during monsoon.

“We had started the tender process for getting four cold-mist fogging machines last year but only one agency took part in the tender and we had to start the tender process again,” said commissioner Kumar. “We will be completing the process by this month and the new agency will be issued work order in March so that fogging activities are started through the new machines by April this year.”

Sources in the RMC’s health department said that of the three existing cold-mist fogging machines, one has developed technical defects and is under repair.

“There are only two fogging machines functional at the moment as one machine is under repair. Since this period of the year (winter) does not witness much mosquito menace we are able to manage with the available machines doing fogging in one ward barely twice a month. However, we would desperately need more such machines during summer as the mosquito menace will gradually increase,” a source explained.

With the availability of the new machines, the total number would go up to seven.

“One cold-mist fogging machine is able to cover two wards a day, once in the evening and once in the morning,” RMC commissioner Manoj Kumar said. “With the availability of seven machines, even if there is damage to one machine we will have six machines at our disposal and we can cover 12 wards in a day and practically cover all the 53 wards in five days’ time.”