It might not have sunk in as yet, but the frenetic building activity going on all over the country could have really serious environmental consequences.

Think of the strain on natural resources like iron ore and limestone; the fast-depleting water table, especially in urban areas; the deforestation resulting from supplying furniture and wooden fixtures to all the apartments; or the power shortfall when these buildings are up and running.

No wonder many Indian developers are looking at green buildings, and green building materials, to minimise the impact of the construction activity on the environment, to help sustain the environment (through rain harvesting, for example), to reduce power bills and, generally, to make buildings that are better places to live and work in.

The figures tell the whole story -- as much as 22 million sq ft of green building space is in the works right now, as against only 20,000 sq ft in 2003. According to a paper published by the Indian Green Building Council in October 2006, by 2010 the business potential of green building materials and equipment in India could be about $3,650 million.

But what are these environment-friendly building materials?

Fly-ash bricks: One of the most common green products in use, not just in green buildings but also in mainstream construction. "Not only do fly-ash bricks solve the problem of disposal of this by-product of the power industry," says S Srinivas, senior consultant at the CII-Sohrabji Godrej [Get Quote] Green Business Centre, which actively promotes green construction practices in India, "but the use of fly-ash bricks keeps the building cooler because they allow only about 40 per cent of the heat of a conventional brick structure."

Other benefits -- it is durable, absorbs less water and is economical. The IGBC centre in Hyderabad uses 20 per
cent fly-ash in concrete to add to its compressive strength. The government's fly-ash utilisation programme has developed pavement blocks, wood substitutes, ceramic tiles and granite substitutes with fly-ash component.

High-performance glass: Glass is a favourite of architects, especially for offices and malls. But the the problem is, glass is a good conductor of heat which means a building that has a glass envelope needs more powerful air-conditioning, which in turn means fatter electricity bills. No wonder the Energy Conservation Building Code announced last year put a 60 per cent cap on the amount of glass used. High performance glazing mitigates much of this problem, especially one that has a low U-value and shading co-efficient.

Increasingly, the trend is to have two panes, set about one-two feet apart, with vaccum or argon gas in the space in between. Not only does it reduce heat ingress, it also lets in daylight and sound reduction. It costs about 30-40 per cent more than conventional glass, but the energy savings mean that the cost can be recovered within three-four years.

Recycled wood: This is wood made by compressing the chips, shavings, and other waste generated by the logging industry and carpenters. The green benefits, over that of virgin wood, are self-evident.

Recycled steel, aluminium, tiles: For a lot of people "recycled" has negative connotations. But, as Srinivas says, much of the building materials used have recycled content - steel 20 per cent, glass 15 per cent, aluminium 35-40 per cent, and false ceiling 12-15 per cent. 

Bamboo products: The best thing about bamboo is that it grows fast, taking about four-five years to regenerate, compared to teak, which takes 40 years. Bamboo also grows locally in India, which lessens the carbon imprint caused by importing it or transporting other green-friendly woods over long distances. Bamboo can be used in the tiles, the wall
cladding, flooring; the Spectral Services Consultants office building in New Delhi, for example, uses a lot of bamboo. Not the least of bamboo's benefit is enhanced aesthetics.

Also, there are a number of manufacturers, especially in eastern India.

Low VOC paints and adhesives: Paints and commercial glue, especially those used to fix carpets, release a lot of volatile organic compounds and toxic chemicals, that adversely affect the air indoors and are even health hazards. Unfortunately, there are not many local manufacturers of such green paints. They have to be imported, and this
naturally drives up costs.

Waterless urinals: This contraption is especially useful in offices and malls where there are a lot of public urinals. When the IGBC wanted to instal these in 2003, it had to import them. But now Indian brands like Parryware and Hindware are available, which has brough the costs down by 50 per cent.

These are zero-water urinals, that is you don't need water to flush or to clean - a blue-coloured, biodegradable liquid does the task. But you've got to be careful with them. The Delhi airport had installed these sometime ago, but has had to remove them when housekeeping staff poured water to clean the pot. The other downside: the liquid has to be replaced in six months to a year.

Green roof: Landscaped roofs help keep structures a whole lot cooler.

Grass pavers: Ever noticed parking lots in malls that are paved but have tufts of grass coming out between the blocks? These are grass pavers -- concrete grid systems filled with soil. These not only prevent what environmentalists call "heat island effect", but also presevent soil erosion and regenerate the water table by allowing excess water to seep in.