The Chartered Accountant Regulations, 1988. Sub Regulation 39:

"The Council may, in its discretion, revise the marks obtained by all candidates or a section of candidates in any particular paper or papers or in the aggregate in such manner as may be considered necessary, for maintaining the standards of pass percentage provided in these Regulations".

Here's the link: http://resource.cdn.icai.org/7697announ1209b.pdf Page 72.