A Bangladeshi environmental group says it has found extremely high levels of lead pollution in the air around the capital Dhaka, causing an enormous health hazard, particularly to children.

The Parash group says lead levels in the Bangladeshi capital have been found to be higher than in Mexico City, generally considered one of the world's most polluted cities.

Many Bangladeshis will be frightened by the findings - but few will be surprised. It has long been obvious to anyone living in Dhaka - which is renowned for its traffic jams - that the city is heavily polluted.

The Parash Group says a recent survey of 100 children in the Dhaka Children's Hospital concluded that 93 had unacceptably high levels of lead in their blood.

Scooters blamed

It is demanding a ban on leaded petrol, the introduction of unleaded petrol and tighter controls on pollution.

Bangladesh now imports crude petroleum, which it refines to produce leaded petrol.

Some economists say it would cost Bangladesh too much to convert its refinery to produce unleaded fuel, but environmentalists argue that the health hazard simply cannot be tolerated any longer.

The Parash Group also wants a ban on two-stroke engines used in scooter rickshaws, which are a popular means of transport in Bangladeshi cities but blamed for causing a lot of pollution.

The findings of the Parash Group will certainly be disputed.

Scientists say lead pollution is highly localized and that the lead content measured on a busy street corner may be far higher than that found only a few metres away.