It is a description that puts a picture into your head while you are reading the said story or poem.
"a. After the rain ended, the sky became blue" would contain an independent clause and a dependent clause, which makes it a complex sentence, since the latter half wouldn't be the same without the former half.
Solution: The pilgrimage is a religious expedition. It has the following effects:
1. It sets the metaphor of a journey both physical and literary. A journey is generally a symbol of human curiosity and growth.
2. A pilgrimage is not only for penance and grace but also a time when people abandon work and take a vacation. therefore it sets a 'carnivalesque' setting. Celebrations are often used in literature for subversion of established social order.
3. A pilgrimage is taken by almost all types of people; therefore it provides apt setting where characters representing different social, political, cultural and economic backgrounds can come together. This way he could reveal more about the society he is criticizing.
This list is not exhaustive, more can be added to it.