as early as the ninth century, "sea coales', found in the northeast coast of England, were burned as fuel. Soon the air was reeking of dirty fumes, making it intolerable to breathe in London. A few centuries later, the then monarch of England, King Edward I (1272-1307), banned its use in his kingdom.

"The air there is polluted over a wide area... to the detriment of their (citizens) bodily health,' said the environmentalist king to his mayors and sheriffs. In his order, he stated that he wished "to take precautions... to provide for the safety of prelates, magnates and citizens'. The king ordered the use of alternative material such as wood.

The king's successor, Edward II (1307-1327), went a step further. Those found fouling the air with coal smoke were to be tortured. But, the order was diluted by the time Richard II (1377-1399) took over. He adopted a moderate position and sought to restrict its use through taxation. Thereafter, Henry V's (1413-1422) reign saw the establishment of a commission to regulate the entry of coal into London.

That was almost 900 years ago. Very little scientific information was available about the health hazards of air pollution then. But it is remarkable how such drastic measures were taken to control it. Today, it is well-known that burning of coal releases particulate matter, sulphur-dioxide, nitrogen oxides and other hazardous substances, all detrimental to human health. But, with the exception of a few countries, most others are yet to wake up to the problems of air pollution.
The beginning of air pollution All the stringent measures that were taken against the burning of coal were, however, rendered ineffective by the 16th century. To meet the demands of the growing population, forest areas were cleared. With no wood left to meet the fuel requirements, burning of coal became essential. Further, with the onset of the Industrial Revolution, the number of fuel-based industries grew rapidly. And the smoke released from poorly designed chimneys started polluting the air.

Transportation was by railroad run by coal-fired steam engines which blackened the neighbourhood. Even as late as 1950, it was reported that in Glasgow, Scotland, three tonnes of soot per acre per year were sprayed by the steam engines. And while the poor lived in filth, the rich migrated to the hills or made weekend houses in the countryside. The court physician of Queen Elizabeth I invented a way of removing the sulphur content, but the process was neither cheap nor reliable.

With the spread of Industrial Revolution, the problems of air pollution spread to other countries as well. The first half of the 20th century witnessed the revival in the efforts to control air pollution. The first method that was adopted was to make tall chimney stacks to disperse the smoke to greater heights in the atmosphere. Heads of states believed this measure was adequate to ensure a healthy environment as smoke released at a height would not return back to the ground via precipitation.

Subsequently, measures were taken to install devices in chimneys to filter the smoke of heavy particulates, thus leaving mostly small aerosols to escape into the atmosphere. Unfortunately, sulphur and nitrogen oxides, being gases, also escaped the devices designed to collect particles. But the problem was not only caused by industrial activity. Most houses in northern Europe and the us were heated by soft coal, and domestic burners used low chimney stacks that had no device to suppress particulate, sulphur and nitrogen oxides.

During the latter half of the 20th century, a few disastrous incidents of air poisoning shocked the world. In December 1930, air pollutants trapped at the Meuse valley in Belgium killed at least 60 people. Sulphur-dioxide concentrations were in the range of 25,000 to 100,000 microgramme per cubic metre (