While one cannot deny that there are power supply bottlenecks, the demand for electricity has also multiplied in the last two years. With this the unauthorised installation of ACs has made matters worse.

The Calcutta Electric Supply Corporation (CESC) has already sent mailers to its customers with Do's and Don't's about installing an air conditioner.

It states: "If you are planning to install air conditioners let us help you. You may be aware that the capacities of meters and other equipment for supplying electricity to a consumer are based on the connected load applied for the consumer. Consumers need to inform the licensee (CESC) if there is any change in this connected load," the mailer states.

The CESC has also appealed to its consumers to inform it in case they have plans to increase the additional load.

"We reiterate and request all our consumers to inform us before installing and connecting any additional load, specially air conditioners, so that we may increase the supply capacity, if required," the mailer, which has been despatched to households with the latest electricity bills, states.

According to estimates made by the CESC, on an average there has been a 50 MW increase in evening peak hour demand as compared to last year.

"The rise in demand is definitely due to increased use of energy gadgets like microwave ovens. In the summer months, it could be attributed to the use of air conditioners," said an official of the CESC.

The shopping malls have also triggered a demand for power in the city. On the other hand, the increase in demand is partly offset by the shut down of industries, said an official of the power department.

Unofficial estimates say that the number of AC installations in Salt Lake itself has shot up by more than 70 per cent, said a senior official of the West Bengal State Electricity Distribution Corporation Limited. A reasonably upmarket neighbourhood of 100 households used to see 30 AC installations. Now 70 households have ACs, a CESC official.

According to an official of Capital Electronics, the last two years has witnessed a 40 per cent increase in window type Acs, mostly used by domestic consumers.