Hello, 

Recents  experience  has shown that the fundamental rights including those of life and liberty, granted to citizens by the Constitution are capable  of  being  taken  away  by  a  transient   majority.

   It  is, therefore,  necessary  to  provide  adequate  safeguards   against  the recurrence  of  such a contingency in the future and to ensure to  the people  themselves  an  effective  voice in determining  the   form  of government  under which they are to live.  This is one of the  primary objects of this Bill.

 It is, therefore, proposed to provide that certain changes in the constitution which would have the effect of impairing its secular  or democratic  character,  abridging  or taking away  fundamental   rights prejudicing  or impeding free and fair elections on the basis of adult suffrage  and compromising the independence of judiciary, can be  made
only  if  they  are approved by the people of India by a  majority   of votes  at  a referendum in which at least fifty-one per cent.  of  the
electorate participate.  Article 368 is being amended to ensure this.

For elaborate explanation, please go through the following link 

http://www.constitution.org/cons/india/tamnd44.htm

Hope this helps...