Answered: Two-thirds majority/Special Majority

Any Majority other than simple, absolute and effective majority is called a special majority.It encompasses Two- Thirds  Majority.

Two- Thirds Majority undertakes 2/3 of Favoured votes, of the total members in house present and subject to voting.It will be accountable only when it is more than the half of total strength of the parliament.

Suppose all the members of Rajya Sabha are present and voting

Special majority would require 2/3rds of 250 = 167 votes.
This number is obviously greater than 1/2 of 250 (=125)
Now, Suppose 150 members are voting and the rest are either absent or abstaining. This is a more realistic case.
Special majority requires at least 2/3rds of 150 = 101 votes
BUT special majority also needs the approval of over 1/2 the total strength of the house (which is 125).
So for a bill to pass by special majority here, it needs at least 126 votes, not just 101.

Special Majority are Used in cases like:-

(a)Under Article 249
Article 249 allows Parliament to legislate in a subject in State List in the national interest. It requires 2/3 or more of members present and voting.
(b) Under Article 312 (Creation of one or more new All India Services)
The resolution must be passed by Rajya Sabha supported by not less than 2/3 of the members present and voting. Then only the bill can be introduced in Lok Sabha.
(c) Under Article 368 (Constitutional Amendment Bill)
The Bill can be introduced in either House of the Parliament. The Bill must be passed by: 1. Majority of the Total Strength of the house (Absolute Majority) 2.Majority of not less than 2/3 of the member of House present and Voting.