Who is the highest tax defaulter in India?

The income tax department, in response to a question in Parliament in 2009, had classified Khan and his associates as the group with the largest outstanding tax defaults. At present, Khan and his associates have outstanding tax dues of Rs71,846 crore, the finance ministry official said.A letter rogatory earlier in the week was issued by the office of the metropolitan magistrate in Mumbai to Swiss authorities asking for help to investigate the financial assets of Pune businessman Hassan Ali Khan.A letter rogatory is a letter of request from a court for some types of assistance.