Here are pros and cons of each subject as far as cracking the IAS examination is concerned:

Humanities have traditionally been termed as the bastion of civil services examination. If we look at data released by the UPSC in their annual reports, we can see that humanities subjects have had a higher success ratio compared to others. Despite, this trend the general participation and success ratio of students belonging to humanities background has seen a downward turn in the last few years. But, despite all these factors, candidates with humanities background still forms a considerable number of aspirants cracking the IAS examination.

Under the current circumstances, we can clearly see that engineering has been the mood and way as far as cracking the IAS examination is concerned. If we take IAS toppers from last few years, it is clearly evident that candidates with engineering background have dominated the examination. While the success ratio of candidates who pick engineering subjects as optional in IAS examination is still on a lower side, we can clearly see that toppers have succeeded with technical subjects. But, in general, engineering is surely the go-to stream, if you want to not only crack the civil services examination but also emerge among the top ranking candidates to be eligible for the IAS posts.

A small but respectable number of candidates from graduates from science stream do take up civil services and crack it regularly. However, their number has not really been great enough to leave an impact on the final tally. But, considering the growing clout of scientific thinking and rising need of technocrats in the bureaucratic setup, it is surely seeing a slow and steady rise.