If you want to reduce this nuisance you have to take some trouble. All the main culprits (ICICI, Citibank, Stanchart, Airtel etc) have websites where you can enter your phone numbers in the Do Not Call register. They do mention that it will take 30 days to take effect. This seems to work. If by chance anyone calls from them you can straightaway say that your number is in the DNC register and hang up. If you are not internet-savvy then get someone to do this for you.
