With the election of 92-year old Mahathir Mohamad as Prime Minister of Malaysia, one has to look closely at the records to see if this is some kind of a new achievement. This is what Wikipedia has to say:
The first table shows Mahathir as the oldest currently serving leader, at 92 years 308 days as of 22/05/2018. He is followed closely by Queen Elizabeth II (not elected, but still….) at 92/23. She is already the oldest British monarch and the one with the oldest reign (since Feb 6, 1952). It may be noted that her mother lived to be over 101. Prince Philip (96+, born June 1921) is currently the oldest consort of a British monarch. Queen Elizabeth’s mother ceased to be a consort in 1952, when she was 52.
There are a few lesser-known names in the top 10, apart from Emperor Akihito (94+, born Dec 1933). It was announced that he would abdicate in April 2019.
The second table deals with “10 oldest ever serving state leaders”. Prominent names here include Malawi’s Hastings Banda (96+ before being removed), Thailand’s Prem Tinsulanonda (also 96+ and still living), Robert Mugabe (93+ before being removed) and Mahathir at 92+.
The third table deals with the longest lived state leaders. Many lesser known persons here, headed by a PM of Cambodia who lived to be 103+.
The fourth table deals with the oldest state leader who is still living. The leader here is a former PM of Vietnam who is now 101+. Other better-known names here include Japan’s former PM Nakasone (almost 100), Perez de Cuellar (Secretary-General of the UN and later PM of Peru) at 98+ and Thailand’s Tinsulanonda at 97+.
Next it goes to youngest serving leaders (which include Kim Jong-Un at 35+, the King of Bhutan (38+) and Leo Varadkar (39+). Not Justin Trudeau who is 47+.
The youngest leaders at the time they took office are almost all royals, some of whom (like King Fuad of Egypt and King Gyanendra of Nepal) who became rulers when they were less than 5 years old. There is one representative from a family of dictators, “Baby Doc” Duvalier of Haiti who became President at 19+.
No representative from India? You have to search for other criteria. More later.