India-Constant Varieties, Error

All errors are varieties but not all varieties are errors,A variety is defined as stamps different in some visible detail of their manufacture from the normal issues ,due to flaws in the process of printing .A variety is called constant when it recures on every sheet or a number of sheet of stamps

1979 Guru Amar Das 'G' Broken
1980 Rubber Tapping .(J Broken)
1981 Tribe,Dandami Maria(Broken
1983 Hemu Kalani 50p.(lip flow)