In simplest terms, weathering refers to breakdown of rocks. The process can be both natural and man-made. Here is a list of human activities that cause weathering of rocks:
- Burning of fossil fuels (in industries, vehicles, etc.) generate sulfurous (i.e. sulfur based) and nitrogenous compounds (i.e. nitrogen based). These chemicals upon entering water and air converts to sulfuric acid and nitric acid, both of which cause chemical weathering of rocks.
- Over-irrigation of crops causes higher run-off (extra water beyond crop's requirements will flow over the land) and causes weathering.
- Dams filter out sediments from river water, making it clean and ready for more erosion of banks.
- Paving of areas for road construction changes the direction and quantity of rainfall runoff and diverts it to newer areas where weathering was not an issue earlier
- strip mining is another source of weathering
hope this helps.