The opening four lines establish that the poem is a memory ("I have thought so much [...]"). In fact, Bhatt is on record saying that it's taken from her own childhood.
These lines also set the scene itself. Like the opening shot of a film, the poem gives the reader just enough detail to sketch out a vivid picture of this memory, while holding back on the more particular recollections and thoughts.
The reader learns that the scene the speaker is recalling took place in Maninagar, a city in the Gujurat region of India. There, the speaker saw a young girl collecting cow dung (a.k.a. manure) in a big basket. The speaker doesn't say why the girl was collecting the dung, but she was probably planning to sell it on for a small amount of money; manure has various purposes, including fuel. That said, this still doesn't seem like the most fun of professions, and there's no escaping the fact that the young girl seems to have had a tough, impoverished life.
There is also a subtle juxtaposition at work here between the sacredness of the temple and the seeming lowliness of collecting animal waste. But that's the point: the poem sets up this contrast in part because it aims to find the holiness and beauty within this young girl herself.
This opening section is pretty light on poetic devices, instead feeling like the speaker is simply having a conversation with the reader. That said, the consonance of the dull /d/ sounds is noticeable is it runs through lines 2 and 3, subtly imbuing the girl's labor with a sense of heaviness:
who gathered cow-dung in a wide, round basket
along the main road passing by our house
Finally, it's worth noting how the opening four lines are all enjambed. This suggests the clarity and intensity of the speaker's memory, which is about to be recreated on the page in full technicolor and smell-o-vision!