Population of 67 millions ? 67 lak is 67 * 100,000. which is 6.7 million.  I changed to have the metro population again.
If you are going to consider "greater  Hyderabad", you had to consider greater Los Angeles ... which might include Los Angeles ...even  Seattle, depending on definitions.  Look at a map of India. The entire subcontinent could be considered one city if you require a defined barren zone  of X km between cities. Metro probably includes the 100th town after the edge of the city anyway.