The most common and most likely answer to this crossword clue is the 6 letter word GANDHI
G
A
N
D
H
I
More clues leading to the result GANDHI
- Head of government also greeting spiritual leader
- Some booing and hissing great leader
- Limits to growth set by one Indian leader
- Somewhat threatening and hideous Indian politician
- Mighty heart, leader in India?
- Pacifist element of Goring and Himmler
- German leads with greeting for non-violent freedom fighter
- Hindu pacifist engaged in booing and hissing
- Film about collaboration between Goering and Hitler
- Political figure’s grand article on democratic Pacific state
Buddy explains!

The straight part
We know that "popular leader" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case popular leader = gandhi.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.