"An Astrologer's Day" is set in India. It is set in a city, but readers are not told what city. However, Narayan created an imaginary city named Malgudi, and it is possible, even likely, that this story is set there as well. (Not certain, but likely.)
Since the collection was published in 1947, readers can assume the story is set prior to this date. That means it was composed in an India that was not yet free of British rule, but that was moving towards it. That said, Narayan is better at capturing the feel of Indian society in general than at portraying specific periods (which does not seem to be his purpose).
An Astrologer's day is set in a marketplace, where traders of all sorts had set up shop. The astrologer in this story was sitting under a wide spreading tamarind tree which bordered the main road leading to the town hall park. He sat from midday until the other traders in close proximity to him packed up for the day. He had no light of his own and was dependent on the light of these traders.
Although there are no clear references to a particular city,it is likely,since Narayab consistently used the fictional city of Malgudi,that this story took place in Malgudi.It was referred to in the story that the astrologer left his home which was in a villageand came to the city.The surroundings o the astrologer as defined in the story give the impression of a somewhat bachward city which still retained a measure of it's rural character.
An Astrologer's Day is set in a rural atmosphere, most probably in the fictional city of Malgudi which Narayan created. Its setting is appropriate because rural people of India still believe in such nonsense as Astrology!!
what is the mood in the astrologers day