not pulling AC is on

I am the second owner of an HONDA CITY 1.3 DX . My car's not pulling well when AC is on. The whole engine feels heavy as soon as the ac is put on.

HONDA CITY 1.3 DX Second owner
Country: India
Kms Done: 1,20,000
Engine Compression ratio prior to overhaul: 140,135,125,145
Engine compression ratio post overhaul: 175 all cylinders (Standard 180 as per HONDA guys)
AC is super chilling but the car pickup tremendously shoots down. On uphill AC cannot be put on.
Servicing of radiator, AC is done well.
Please suggest me the solution to solve this problem.