"The largest populations that rely on traditional biomass for energy are in the developing regions of Asia, with 836 million in India alone," said a new research published by the Worldwatch Institute for its Vital Signs Online publication.

"Altogether, 54 per cent of the population of developing Asia relies on traditional biomass fuels," said the report, according to which despite massive gains in global access to electricity over the last two decades, governments and development organisations must continue to invest in electrification to achieve critical health, environmental, and livelihood outcomes.

Between 1990 and 2008, close to 2 billion people worldwide gained access to electricity. But the International Energy Agency (IEA) estimates that more than 1.3 billion people still lack access to electricity, while the UN says that another 1 billion have unreliable access, it said.

The report said at least 2.7 billion people, and possibly more than 3 billion, lack access to modern fuels for cooking and heating. They rely instead on traditional biomass sources, such as firewood, charcoal, manure, and crop residues, that can emit harmful indoor air pollutants when burned.

These pollutants cause nearly 2 million premature deaths worldwide each year, an estimated 44 per cent of them in children. Among adult deaths, 60 per cent are women.

Traditional energy usage also contributes to environmental impacts including forest and woodland degradation, soil erosion, and black carbon emissions that contribute to global climate change, it said.

Meanwhile, a senior Obama Administration official said India and China would account for more than half of the increased energy consumption in the world by 2035.

"Our latest international reference case projects worldwide energy consumption growing about 53 per cent by 2035 with China and India accounting for half of the increase," said Howard Gruenspecht, Acting Administrator, Energy Information Administration; at a Congressional hearing yesterday.

"While fossil fuels continue to dominate, renewable energy is projected to be the fastest-growing source of primary energy. Natural gas has the fastest growth rate among the fossil fuels, and developing countries really dominate the growth in all categories of energy use," he said.

"As new approaches to electrification evolve, ones that don't rely on expensive regional or national grids but rather a diversity of locally available energy resources, we can begin to reach for the goal of access to electricity for all, rural as well as urban," said Worldwatch president Robert Engelman.