In 2015, CSAT paper was made qualifying, just to appease a section of students having agitational skills. The protests which eventually led to removal of CSAT was organised and led by certain Coaching institutes, who were unable to adapt to Aptitude test.
The prelims pattern since 2015 with CSAT Qualifying, came as an ad-hoc arrangement not supported by any expert committee. Later this decision (which was not supported by committee expertise but brought about under pressure & agitations) was made permanent without studying its negative effects which are very clear now.
The prelim pattern since 2015 has led to heavy crowding effect around cut-off marks and selection of candidates based on one paper performance. Thus UPSC prelims has become a mere gambling where thousands of non-serious candidates get through by indulging in wild guessing (Tukka).
Hence, instead of one paper, UPSC prelims should have two papers & more number of questions to screen out non-serious candidates, as compared to only 100 questions & a mere 2 hours of general studies paper to evaluate candidate's suitability to face mains examination.
Kindly request you all believing in scientific temperament, logic and rationality to join the following facebook group in support of the above ideas:-https://www.facebook.com/groups/2063746170560363/