The Shiromani Akali Dal, one of the oldest allies of the BJP, on Saturday said it was quitting the ruling party's National Democratic Alliance (NDA) after sharp differences over the three controversial farm sector bills adopted earlier this month. Akali Dal chief Sukhbir Singh Badal had earlier said the Akalis - who initially supported the bills - are reviewing ties with ruling party, and had also requested President Ram Nath Kovind to "please stand by farmers" and not sign off on the laws.