Sir: Having worked as an agronomist for 20 years on sustainable agriculture and other conservation projects in the rainforest area of south-east Mexico, I have been very pleased to see the coverage given to the ecological disaster in Indonesia.

However, it needs to be pointed out that this smoke pollution happens every year during the "burning season", whether in Mexico, South-east Asia, Amazonia or Africa. Airports are sometimes closed. The smoke can hang around for up to a month, depending on the winds and whether the rains arrive early or late. Rural as well as city people suffer from the pollution, but it is exacerbated by the industrial and traffic smog of cities.

Burning to clear ground for crops is an ecologically disastrous process. Much of the potential nitrogen is lost in the burning of the vegetation; a lot of the rich ash is washed away by the heavy rains at the beginning of the rainy season; the structure of the soil is broken down, partly by the fires and partly by the baking of the sun on a soil which has always been protected beneath the shade of the trees and the layer of leaf-litter. The only advantage is that clearing land by burning is quick and easy and gives a good harvest in the first year. But it is destructive in the long term.

It would be to the benefit of the whole world if the media could continue coverage of this topic and not discard it as soon as it is no longer "news".

The Rev BOB SHORT

Repton, Derbyshire