The mother in the story puts on a "fresh sari to help her face the summer evening." A sari is traditionally worn by women who live in the Indian subcontinent. While it is true that Indian women living in America wear saris, there are other things in the story that suggest a different setting.

The children are described as having had their "tea," which in countries ruled by Britain refers to both the drink and an afternoon meal. This reference deepens the idea that the location is likely India.

When the narrator observes that "a band of parrots suddenly fell out of the
eucalyptus tree," it further suggests an Indian subcontinent setting. The tree is known to grow there, and parrots typically are not found in great numbers in the U.S.

And finally, the names of the characters in the story are not popular names in America: Ravi, Raghu, Mira, and Manu.

The first paragraph clues the reader in to the fact that the story is not happening in the United States.  The main hint in that paragraph for me is the fact that the children had "tea."  Tea is not an American thing to have.  Sure, my grandma likes tea, but sitting down for afternoon tea is not a typical American thing.  

The next clue for me is the first line of dialogue.  

"Please, ma, please,'' they begged. "We’ll play in the veranda and porch—we won’t go a step out of the porch.''

"Veranda" and "porch" are not typical American words either.  Kids might play on the patio or the deck, but not the veranda/porch.  

The final big clues to the reader are the names of the kids.  Raghu, Manu, and Ravi are not typical American names.  Those names suggest southeast Asia.  The narrative being in English and characters having tea then suggests an English speaking Asian country.  My best guess is India, since at one point it was part of the British empire.