I want to pursue a diploma in mechanical Engg.through correspondence

Name: G.srinivasu
Message:
I have passed two years I.T.I course in fitter trade WITH 78.2%. NOW I
am working as a fitter in m/s Satluj Jal Vidyut Nigam Ltd, Jhakri,
Shimla dist, (H.P). I have 10 years working experience as a fitter in
hydro power stations .I want to pursue a diploma in mechanical
Engg.through correspondence which will be helpful in enhancing my
career prospects. Can you please suggest some good options?