Sid-day

It's celebrated on 17th of August as per the popular Indian sitcom named "Philophers". The character Sid, who goes by the name "beerbottle", makes it rain beer for his friends. His friends start calling it the Sid-day.

yasho: bruh, why is it raining beer today?
sunil: brah! it's sid-day gif!
kena: here, fill my cup too. i can't come.
rajjo: wait. i am coming too.

AMJ

It's short for "Aaj Maine Jana". This is a Hindi version of "Today I learned". It is popularized by the subreddit r/AajMaineJana

raj: amj, how railway tunnels are cleaned.
me: so, where you gonna use this knowledge then?

Indian GIF day

It's celebrated on 4th of May as per a popular Indian sitcom named "Philophers". On this day, you can only use GIFs and not words to reply in chats. This is majorly popular in Bihar, Uttar Pradesh, Gujarat, and Rajasthan states of India.

yasho: bruh, it's indian gif day, finally!
sunil: yes i know murga gif!
yasho: "agreeing gif"