Pakistan did not remove their forces which was the prerequisite for plebiscite.. After a significant time passed, India walked away from the agreement because of this delay on Pakistan's part. This duplicity of Pakistan is exemplified by the fact that even today, Pakistan has not yet complied to the prerequisite to the plebiscite..
Nehru decided to not to hold the plebiscite in 1948.
I think even for Nehru, there should be trial for lying to the UN, Kashmiris and even his own people when he addressed the lok sabha.