Where in India is telephone area code 0140?

Telephone area codes (STD codes) in India beginning with 014 (or +91 14 in international format) are generally in Rajasthan state, but 0140 (or +91 140) is a special case.

The 0140 code has been assigned to the registered telemarketers for fixed line and mobile networks.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)