The air in Mumbai was very smoggy the entire two weeks we were there. The smog pretty much covered all of central India, causing lots of flight delays and some cancellations.

The prevailing opinion is that the brick-making operations in central India are a primary cause of the smog. India consumes a LOT of bricks. On our drive from Agra back to Delhi we passed what seemed to be more than a hundred brick factories, all spewing smoke out their tall stacks.