What is a reliable source for covering old old PYQs? The official answer keys are available up to 2013/14 on the UPSC website i think. If older ones are available online from an official/reliablr source please lmk. Or any publication which has a collection of the actual official answer keys (and not their own estimations of what the answer would be) for 25-30 years (or more if possible and needed)?
Afaik there was no official answer key concept before 2011-13.
I've referred to La excellence pyq compilation for the answers, they also provide detailed solution for each question thus their answers holds some credibility.
