The Indian rupee slumped 18 paise to 73.53 against the US dollar in opening trade on Tuesday tracking weak domestic equities and strong American currency. Forex traders said concerns over rising Covid-19 cases also weighed on investors` sentiment.

At the interbank foreign exchange, the domestic unit opened lower at 73.47 against the dollar, and lost further ground and touched 73.53, registering a fall of 18 paise over its previous close.