Dear Aspirant,

India is dusty due to two reasons:-

(i) Natural: Its mostly limited to desert areas and is prevalent in parts of west Rajasthan only. We Indians are quite lucky there. Ask this to someone from Arabia and you'll know what it really means.
(ii) Man-made: This is common to almost the whole urban world! Deforestation, soil-erosion, cutting the jungles. This is man's way of saying THANK-YOU to nature. And DUST is our return gift!

We have a very peculiar seasonal climate. In monsoon the land is completely drenched for four months which gives impetus for the growth of plants. This creates cracks in the rocks and soil (due to the roots ofcourse). And then we face 8 months of dry climate where all of these so called weeds die leaving behind the soil and rock ready to be eroded by the wind, this is known as denudation. Anyhow, this cycle has been going on in our lovely country for a long time now, causing a lot of withering and creation of dust particles.

Plus the winds that blow from the Arabian desert gets us a gift of tons and tons of light sand which gets deposited in western India.

Hope this helps.

Good Luck!