In the book The Great Arc, John Keay writes this about the Trigonometrical Survey of India that started in the earlier part of the 19th century:

Survey work was conducted during and immediately after the monsoon because, regardless of the discomfort, it was only then that the dust was laid and the heat-haze dispersed. In the interludes of bright sunshine, the atmosphere was at its clearest. . .

To me, this suggested that, for the surveyors, this problem was unique to India and they might not have faced this issue in places such as England (or maybe this conclusion is wrong?)

Since this was in the earlier part of the 19th century, there was no pollution due to factories or cars. The surveyors would often be away from villages and towns so probably no pollution due to human activity (cooking fires etc.,).

Does this imply that the subcontinet is hazier/dustier than other parts of the globe?


1 Answer 1


There were two sources of solid matter polluting India air during the 19th century, that are still applicable today: farmers burning stubble and dust raised from arid regions during dry, hot windy periods.

In Britain and Europe during that period, dust raised from arid regions would not have been a usual occurrence. As, happens in the contemporary period, both would have experienced occasional dust storms from the Sahara Desert.

The burning of stubble would have been practiced in Britain and Europe. It is questionable whether England would have experienced hazy conditions due to this during that time due to prevailing wind conditions and the amount of stubble that would have been burned.

The comment made by the British surveyors in India at the time does not suggest air pollution conditions were neither better or worse than those in Britain at the time. I read it as a comment on how conditions were in India when they needed to do a particular survey and why they chose to conduct the survey when they did. Limited visibility due to air pollution makes surveying difficult because it reduces the length of the lines of sight and result in misreading of survey targets.


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