I posted a similar question and did not receive any responses. I tried to find out from other sources with no luck.
Can anyone please tell me if I want to avoid fog and am travelling in December where I should not go?

Many Thanks, I really appreciate it.

I already posted this on your other tread....

Fog is an issue in Delhi, Jaipur, Varanasi and other parts of Rajasthan and northern India in the winter months. It forms in the early morning and evening hours around sunrise and sunset, and does lead to flight delays at airports. This is greatly exacerbated at Delhi airport by the fact that both the domestic and international airports are too small for the traffic they handle, so flights can easily get delayed even without the fog issue. If you can, try to avoid early morning or early evening flights; but as noted above, once flights start to get delayed, all subsequent flights get backed up as well. (This is not such a problem in Udaipur, Varanasi and Jaipur as these are not the main business airport like Delhi, it is more often fog that is just the issue at those airports; there are also fewer flights in and out of these airports.)

One way to avoid this is to avoid flying domestically when possible, esp out of Delhi. Take trains when you can, i.e. you can take a train from Delhi to Jaipur rather than flying. The train takes about 5 hours. Use a car where possible as well, for example, you can drive from Agra to Jaipur in about 3 hours, with a stop at Fatephur Sikri on the way.

If you want to avoid fog altogether, you need to go to South India, but my guess is that you want to see the Taj Mahal and the mughal architecutre of nothern India. South India is very interesting, but not typically on the first-time tourist's itinerary for India. But look at your guidebook and consider places like Goa, Kerala for beaches, or Chennai, Madurai, Trivandrum or temples and some old colonial flavour. Also consider Hyderabad.

a. The problem of fog centres over north Indian reverine basin. The cities most likely to be affected are those which situate around the rivers. If we talk about the Golden Triangle, the most affected parts would be Delhi. Agra will have slightly lesser densities of fog, doing no good for an early morning viewing of Taj Mahal.But you can still drive & visibility not all that poor. Rajasthan shall be totally free of it. As you move towards Jaipur, the fog begins to disappear from Manesar (about 30 miles from Delhi).
b. Varanasi again will be enveloped by fog, disrupting train / air flights.
c. The problem is acute from say 15th December for about a month.
Hope it helps.

Thanks for your time and thoughts.Today I'm thinking I'll just deal with the fog
and stick with my original plans but will do some research on the south first.

Thank you