Ever since Tyrolean travellers to Nepal in the early 17th century described Kathmandu Valley as "the dirtiest place in the orient" we seem to be trying our best to live up to that status.

That was a time when the entire Valley had no more than a population of 10,000. Today, it has swelled to nearly 1.5 million and it is clear we are now reaching the limits of growth. A metropolis of this size needs either a major river running through it to flush itself, or has to be situated near a sea. We just have three spring-fed streams that by now have turned into sewers.

It is a myth that Kathmandu is a valley. Actually it is a plateau, the terrain beyond the valley rim on all sides dips down to less than 900m. All these natural impediments pale in comparison to the human bungling that has turned one of the most spectacularly-located and culturally-vibrant capital cities in the world into a toilet bowl. The fact that Kathmandu's old-world charm shines through all the grime, concrete and foul air is a tribute to our ancestors. They left us a legacy of beauty and architectural harmony, but what legacy are we leaving for our grandchildren?

It is said that the test of a civilisation is the way it treats its waste. Well, we don't treat it. On that count alone, we fail miserably to attain a civilised status. The raw sewage emptying into the Bagmati, the industrial waste that makes this holy river froth at Chobar, and the powerful odour of death over the bridge at Kopundole all remind us of our own callousness.

Then there is the growing garbage crisis, each time we pass the neighbourhood heap, the stench reminds us of our inability to separate and turn its organic constituents into valuable fertiliser, and the failure to stop the growth of non-biodegradables like plastic bags.

Even more shocking is our breathtaking disregard for air quality. As our investigative report in this issue ("Gasp") makes clear, we are choking ourselves to death. The paradox here is that we know it, we know what should be done about it, we have the laws in place to do it, but we still can't do it. There are lessons from how New Delhi managed to turn itself from one of the most-polluted cities in Asia to one with one the cleanest air in three years ("How Delhi did it").

Here in Nepal we have great laws, the world's best, in fact. Our zoning laws, the municipality's architectural guidelines for new housing, the rules for garbage collection. We have emission standards for vehicles, there are supposed to be tariff incentives for electric transport, and fuel adulteration is a crime.

Yet, every 30 litres of diesel sold in Kathmandu's gas stations has 15 litres of kerosene mixed with it. This is kerosene supposedly subsidised to make energy more affordable for the rural poor. What is coming out of the tail pipes of the buses and cars on our streets is therefore benzene, an invisible carcinogenic gas.

Take a peek at the furnaces of the brick kilns on the town's outskirts: they are burning plastic trash and old tyres to bake bricks. Think about that the next time you buy a lorry load of bricks. Or the next time you take a deep breath. And then think again what we can all do as responsible citizens.