Named 'dengue-free cooler' and designed by the National Centre for Disease Control (NCDC), the North Delhi Municipal Corporation claimed, they were equipped with facilities to reduce breeding of mosquitoes inside it.
A net placed above the water tank of the cooler keeps away mosquitoes from breeding in water, said NDMC Commissioner P K Gupta.
The leaves of agave americana are used to destroy mosquito larvae. The extract of its crushed leaves is used in particular amount as per the capacity of the tank that destroys the larvae growth within 1-8 hours, he claimed.
The campaign was launched by the NDMC leaders and officials from City Zone of the civic body.