Don't do airdrops based on social media accounts! Make airdrop based on holding some other asset at given time.
Like CLAM (every address holding BTC, LTC or DOGE in may 2014 received 4.6 CLAMs) or RHT (NEO address holding between 1 and 99 NEO in dec 2017 received 1 RTH) ...
This. Though there would be "the rich gets richer" counter-arguments, this is probably the best choice we have right now if you want to prevent individual people from claiming multiple airdrops, and at the same time, without accepting KYC.
Linking everything with Telegram might be a good idea. Since you cannot have 10 different Telegram accounts. This might restrict it a bit further
Why can't you? Mobile sim cards are pretty cheap.
It seems scamming airdrops can actually be pretty good business, specially if you live in a country with low wages