Punjab's pesticide use per hectare is among the highest in India, concentrated in the cotton and paddy belts. Consumption rose steeply through the Green Revolution decades and has fallen somewhat since, partly through Bt cotton and partly through regulation.
Spurious and mislabelled product is a persistent problem and has been the subject of criminal cases, notably after the 2015 whitefly outbreak in the cotton belt.
Residue is a trade problem as well as a health one. Export consignments of basmati and other produce have been rejected in Europe over residue limits, which led Punjab to ban several molecules on basmati.
Health claims about pesticide exposure in the Malwa are widespread and the epidemiology is contested. Groundwater studies have found pesticide and heavy metal contamination in parts of the belt at levels above drinking water standards; whether that translates into the cancer incidence claimed is not established.
The honest position is that the exposure is real, the contamination is measured, and the health consequence is argued. Anyone stating it more firmly than that in either direction is going beyond the evidence.
The application is done by hand with a knapsack sprayer, usually without gloves or a mask, and often by hired labour rather than by the owner. The exposure that matters most is the sprayer's and it is the least studied.
Residue has been measured in food, in water and in blood samples in the belt, and the studies that exist are small and have not been repeated at the scale needed to settle anything.
The regulatory system controls what may be sold and not what is applied. A farmer buys advice from the dealer selling the chemical, which is the structural problem underneath all of it.
Punjab agriculture department pesticide consumption data.
EU residue notifications.