Explanation:

- 1949: The Reserve Bank of India was nationalized in 1949. This pivotal move marked the first step towards centralizing bank control under the Indian government. However, this did not include the nationalization of commercial banks.

- 1955: The Imperial Bank of India was nationalized and renamed the State Bank of India in 1955, aiming to extend banking facilities especially to rural and semi-urban areas.

- 1969: This was a landmark year when 14 big commercial banks were nationalized to increase government control on financial institutions and to ensure banking services reached different parts of the country, especially rural areas.

- 2000: By this time, many banking reforms were underway but no nationalization of major banks happened.

1969: 14 big scheduled commercial banks were nationalized.