Time limit for issuing notice u/s 148

Malay (NA) (143 Points)

17 October 2018  
Suppose a notice u/s 148 for A.Y. 2011-12 dtd 31.03.2018 is sent by AO by speed post, then by what time it will be received by assessee at the earliest ? Can it be barred by limitation (6 years in this case) ?
Also, if notice is sent by email on 31.03.2018 at the email address abc @ xyz.com, but xyz.com has stopped providing email services from 2013 onwards, then will it be deemed that notice is served to the assessee ?
Kindly respond by considering the above case with reference to the sections of the Income Tax Act.