Interpreting word 'may'

Here, it means, if he chooses to file an appeal, then it has to be filed within thrity days from the reciept of such decidsion. If he does not chose to file an appeal, then the question of filing of an appeal does not arise at all. 

you are correct

I believe that your  presumption is partly right.  The time-frame of 30 days is relevant only if and when an RTI applicant desires to file an appeal.

dear  Sirs ,

thanks for prompt replies .

Suchitra is right! 

The computation of limitation is starts from the reciept of the copy of judgment and decree. If the party applies for the certified copy on the same day of the delivery of judgment, the days for delivering the certified copy shall be ommitted in the calculation. If the application for certified copy is not filed on that day or on subsequent day of delivery of judgment, this can not applies. Then the delyed days will be calculated in that thirty days. See the Limitation Act.   

there is another remedy u/s 18 -- direct complaint to Information Commission . Remedies u/s 19(1) and 18 have same pre-conditions , these are parallel , independent remedies .

My query is .... presence of word MAY [ as mentioned in first post ] , does it give me a choice [ may or may not ] to avail another parallel remedy if I have  .

If 'May' is is interpreted as 'can' ..then also there is hardly anything to call it inappropriate.

But legal wording 'may' is always preferred as it is formal.

If the applicants waits for more than 30 days even after the expiry of the prescribed date of decision, ......... in the hope that ............. atleast after  delay  ................ decision would be dlivered ....  but in vain ... then also he may/can appeal any time ............. if he chooses to do so ......... as every next day after 30 days also .... is the acnticipated date of "delayed decision".

Otherwise applicant would be remedyless.... as every charter of any institution place words like 'as far as possible and practicable to so ........ '  

Or one should ask condonation of delay at appeal ........ saying that ............ he waited so long ..... in the hope that at least after delay, decision would be delivered.