Interest rate risk is the chance that a bond fund's NAV falls because interest rates rise, which lowers the price of the bonds it already holds.
Bond prices move opposite to interest rates. A bond paying 7% becomes less attractive when new bonds pay 8%, so its price falls until its yield matches the market. When rates fall, the older bond's price rises.
A debt fund's NAV moves with the prices of its bonds, so it rises when rates fall and falls when rates rise.
How much depends on modified duration. A fund with a modified duration of 6 would lose about 6% if rates rose by 1 percentage point, and gain about 6% if they fell by as much. A fund with a duration of 0.5 would move about 0.5%.
As a result:
Interest rates in India move mainly with the Reserve Bank of India's policy rate and with expectations of inflation. Over a long holding, a fund reinvests maturing bonds at the new rates, which over time makes up some of a price fall.
Each fund page has its returns, risk, costs, managers and everything it holds.