Are you sure it's not 5 sqmm is it really 0.5sq mm. Even the village electrician won't do such things. If its really 0.5 sq mm chances are that the owner and electrician who did this also cheaped out by not providing earth to three pin connections.The building I'm living in (on rent) has 0.5 sq mm wires for 16A sockets as well.
The bank in front my house constructed in 07 doesn't have a earth in the ATM. Nor is earth there in the dual 5kva online UPS room which powers the bank.