NEW DELHI - They are smelly, noisy, polluting and expensive - and increasingly, they are what keep India running.
The massive electrical grid failures that India experienced on Monday and Tuesday would have been catastrophic in many other countries, leaving hospitals without crucial power for lifesaving machines, airports paralyzed and businesses shuttered.
But in some parts of India, particularly urban areas, office parks and wealthier neighborhoods, the failures were barely noticed. State-run electricity is already so unreliable that residents and businesses long ago resorted to buying private diesel generators to produce their own.
In Lucknow, for example, the Vivekananda Polyclinic and Institute of Medical Sciences, a private hospital, was using three generators Tuesday to keep dialysis machines running and air-conditioning on in the wards, said Sachendra Raj, the hospital's manager.
Six hours after t he blackout started on Tuesday, Dr. Raj said he was unfazed. “It's part and parcel of our daily
 life,†he said. The situation in his state, Uttar Pradesh, may get worrying once residents' smaller generators run out of power, he said, but his hospital's industrial-size generators will last longer.
Entire industries and neighborhoods rely on diesel power, including India's massive call center and outsourcing campuses, private apartment buildings and small shops. The city of Gurgaon, south of New Delhi, has been heavily dependent on diesel for years. Even the most utilitarian things, like the telecom towers that help power India's much-vaunted mobile phone revolution, are often powered by diesel.
Estimating how much diesel Indian consumers use to make up for the state's energy shortages, or how many people own such generators, is difficult. More than two billion liters, or 5.3 million gallons, of diesel are used every year just to keep India's rural and urban digital communication network running, according to one 2010 report.
Diesel fuel in India is subsidized by about 13 rupees (about 23 cents) per liter, about a third of the sale price, and when the cost of these subsidies is taken into account, diesel is more expensive, on a per-kilowatt-hour basis, then even the most expensive renewable energy in India, a 2010 World Bank report said.
An extremely hot summer and the recent power failures have meant a booming business for diesel generator sales. “This is a good year for us,†said Irfan Ali of Sunshine Diesel Engineers, a rental and sales shop in Noida, a suburb of New Delhi. “Power cuts have been more frequent.â€
After reports of power failures began on Monday, calls to Mr. Ali's shop doubled, he said. Some customers are renting generators, while others are buying a second one, he said.
Sruthi Gottipati and Niharika Mandhana contributed reporting.
