What is anti-defection law? Do you think that anti-defection law in India is weak?

What is anti-defection law? Do you think that anti-defection law in India is weak? (GS 2)

एंटी-डिफेक्शन कानून क्या है? क्या आपको लगता है कि भारत में एंटी-डिफेक्शन कानून कमजोर है?