Article 70 also called Anti-defection law law or Anti floor crossing law.

Article70: violation of Seat on resignation or voting Against the party:

A person elected as a member of parliament at an election at which he was nominated as a candidate by a political party shal vacate his seat if he-

(a) resign from that perliament

(b)vote in parliament Against that party.

So a member of parliament (MP) who is elected by his people can not give his opinion rather he has to always support his leaders decision. Otherwise he will dismissed from his party.