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?