Two volunteers wore tiger bodysuits and posed inside a cage as part of their "Save the Tiger-Say No to Zoos" campaign.
"If human beings cannot be in a cage for an hour, why are animals caged inside zoos?" one of the volunteers said.
The protest was organised in the wake of deaths of six tigers in the zoo within a span of six months.
"The big cats suffer from Obsessive Compulsive Disorder when kept in cages and become depressed.
"Typical traits like head-bobbing, pacing up and down and inflicting self injuries become common," said PETA India Campaign Adviser, Bhuvaneshwari Gupta.
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She added that a big cat usually needs an area 1,800-times bigger than the size of the average enclosure in an Indian zoo.
"Tiger-protection efforts must ensure physical and mental well-being of the animals... Nobody wants to be caged," Gupta said.
The protest also marked International Tiger Day, which is on July 29.