India became a member of the G20 as a founding member when the G20 was initially formed. More specifically, India has been part of the G20 group since its inception in 1999 as an international forum for economic cooperation among major economies. India's significant milestone in its G20 involvement came when it assumed the G20 presidency on December 1, 2022, and convened the G20 Leaders' Summit for the first time in India in September 2023. The 2023 summit in New Delhi was the first G20 summit held in India, marking its active leadership role in the forum.

So, in summary:

• India is a founding member of the G20 since its start in 1999.
• India assumed the G20 presidency on December 1, 2022.
• India hosted its first G20 leaders' summit in New Delhi on September 9-10, 2023.