What is a 'benchmark' in mutual fund performance evaluation and what was SEBI's major change in 2018?

EXPLANATION

A benchmark is the index against which a scheme's performance is measured. SEBI's major 2018 change required AMCs to use Total Return Index (TRI) — which includes dividends from index stocks — instead of Price Return Index (PRI). Since mutual funds also receive dividends, comparing with TRI is fairer and more accurate, generally making it harder for funds to show outperformance.