How many banks were Nationalised in 1980?

Six scheduled commercial banks were nationalised in 1980. The banks which were nationalised in 1980 were Vijaya Bank Limited, Punjab and Sind Bank Limited, Oriental Bank of Commerce Limited, New Bank of India Limited, Corporation Bank Limited, Andhra Bank Limited. It was done through the Banking Companies (Acquisition and Transfer of Undertakings)Ordinance,1980. You can read about The Reserve Bank of India: Functions and Composition in the given link.

Further readings:

1. Non Performing Assets (NPA) – Facts for UPSC GS-III
2. Topic-Wise GS 3 Questions for UPSC Mains