The Civil Services Examination is based on the British Era Imperial Civil Service tests, as well as the civil service tests conducted by old Indian empires such as the Mauryan Empire and Mughal Empire. It is one of the most difficult competitive examinations in India. A single attempt can take two complete years of preparation – one year before the prelims and one year from prelims to interview. On Average, 900,000 to 1,000,000 candidates apply every year and the number of candidates sitting in the preliminary examination is approximately 550,000. Results for the Prelims are published in mid-August, while the final result is published in May of the next year.