Are you sneezing continousely irrespective of the climate in bangalore?
If yes then 99% chance that you are having dust allergy. Bangalore atmosphere is worst because of the dust it produces.
When I migrated to bangalore in mid 2000, I was not having any trouble with dust. The only unusual thing I noticed was the itching when exposed to Sun. When I walk through the roads in Sun, the "itching" will start soon and it will last for 2 to 4 minutes. It was very uncomfortable and I feel "itching" all over the body and I cannot explain how it feels in writing. But after 2 years that problem was gone and I felt i was mingled with bangalore atmosphere till I got the sneezing problem in late 2005. When I start sneezing it will last for 2 minutes.
First I consulted an "ayurvedic" doctor and the treatment was helpful for 1.5 years. The problem again started and then I consulted Dr Anil Kuztagi in Wockhardt hospital. He has done blood testing and gave me a medicine to inhale [ Flexinasal Spray] and some medicines. Now the sneezing is stopped and God only knows till when.
So bangaloreans "beware of dust" - Like you, I also don't know how to avoid it - Have a nice day!