India's phone system is the second largest in the world based on the number of users.
Country code: +91
Simple to use number tracer - find out where a number that called you is located, whether it's a mobile or landline and who the carrier is. Doesn't give the name of the person who owns the number though.
White Pages directory for Delhi, Mumbai, Kolkata, Bangalore and Chennai. Type in the name of the person or company you're looking for in the first search box - fast response time but the result format is very untidy. It's returned in a new window as a Google style search result with each entry being a new item. You need to scroll down and click on the name to get the number (and address). Reverse search (the second search box) is very unreliable and you need to select the city first. Uses data from BSNL.
Excellent White Pages for Mumbai. Find people, businesses or check by number (reverse search). Requires a captcha to be completed to prove you're human before search results are shown. Fast response times and detailed information is provided such as addresses as well as numbers.
Phone Book for New Delhi, includes searches for people, businesses and phone numbers (reverse search). Clear instructions are provided by the directory search options and includes wildcard options.
Yellow Pages for Bangalore, Chennai, Delhi, Hyderabad, Mumbai, Ahmedabad, Kolkata and Pune.
Yellow Pages busines directory for Calcutta (Kolkata) in West Bengal.
Yellow Pages directory for the Tamil Nadu region.
Indian Yellow Pages and business directory. You need to select a location as well as the type of service or company name. Once the search results are shown click on 'Contact Me' to get the full listing including number.
Comprehensive Yellow Pages site of Indian businesses in the USA searchable by business or area code.
Telephone Directory Enquiries for West Bengal region. Find a person by first name, surname, phone number (reverse search) and address. Find a company by name or organisation. Very slow response times and currently the reverse search is limited in good results. It requires a city to be entered (so search is impossible if you don't know) and a number which was tested on other directory sites successfully wasn't found.