Hello! Narayan's The Vendor of Sweets is situated in the 60s in post-independence India, and can be analyzed as post-colonial writing in terms of its main themes:
1) The generational gap between Gandhian tradition and Western modernity.
2) The conflict between spirituality and materialism in post-colonial India.
1) Gandhian tradition and Western modernity
In the novel, Jagan the protagonist is a prosperous widower who is a sweet vendor in Malgudi. He is a strict vegetarian, believes in naturopathy and espouses the Hindu belief in ahimsa (non-injury to others). He spins cotton on his charkha (domestic spinning wheel, used chiefly for cotton) and wears clothes made from khaddar (homespun Indian cotton cloth). He does not even use toothbrushes for fear the bristles might be made from pigs-tails. He relies on his beloved Bhagavadgita for wisdom and is horrified that his only son, Mali, chooses to depart from the traditional Indian beliefs he raised him with. When Mali decides to pursue a career in writing and aims to go to America, Jagan is broken-hearted. Mali claims he is tired of the old ways and of the Indian educational system. He is ready for something new. The generational gap between father and son is fueled by two competing ideologies. Mali, perhaps, holds no small resentment towards his father for his mother's death from a brain tumor. He has much more faith in western medicine than the old Indian ways of his father. Mali further horrifies his father by bringing home a Korean-American wife named Grace, and later grieves his father deeply when he claims that he never married her. The old Indian tradition of parents choosing their offspring's spouses is turned on its head. Indeed, Mali even exhorts Jagan to eat beef.
I’ve taken to eating beef; and I don’t think I’m any worse of it . . . Now I want to suggest why not you people start eating beef? It’ll solve the problem of useless cattle in our country and we won’t have to beg food from America. I sometimes feel ashamed when India asks for American aid. Instead of that, why not slaughter useless cows which wander in the streets and block the traffic?
Mali has violated the first of five Hindu shastras (rules); to kill a cow and to eat its meat is anathema to Hindus.
2) The conflict between spirituality and materialism
Jagan has to decide who he is in his final years: is he the faithful Gandhian follower who finds great joy in living his life according to his beliefs, or must he reconcile his personal tenets with his ability to accumulate wealth largely through tax avoidance? Ironically, his Gandhian virtues rub his relatives the wrong way in post-colonial India, but he is happy to hold on to his values as it prevents him from having to attend tiresome family gatherings. According to the Shastras, everyone has three earthly attachments–Dareshana (wife), Putreshana (son) and Dhaneshana (wealth). Jagan reconciles his Gandhian ways of non-attachment and non-possession with his materialistic accumulation of wealth by rationalizing that he is just performing necessary work for the purposes of self-determination as Gandhi would have liked. Also, since he will be leaving it all to his son, he sees no reason to change his ways. In the end, he asks his "cousin" to look after the shop until Mali takes over. He is more than ready to begin his quest for finally conquering his earthly attachments and to realize his search for self-actualization.
Thanks for the question. I include relevant and interesting links below from an Indian perspective of the novel.