Increment rules

i m working in railways as Junior engineer (Elect)GS

i have doubt regarding increment rules

i m sick without pay from 01.01.2010 to 02.08.2010

and    maternity leave from 03.08.2010 to 29.01.2011

and Child care leave from   03.01.2011 to 29.04.2011

please clarify am i eligible for increment in July , 2010

already i got increment in July 2011

but i dont get July 2010

please give me answer