This is the 4 Annas green King George V definitive of British India, overprinted “BURMA” in black and issued in 1937, when Burma was separated administratively from India. Your example shows a clear inverted overprint, where BURMA appears upside-down relative to the base design — a desirable and scarcer variety sought after by specialists in British colonial issues. The intricate Indian ornamental frame, portrait of King George V, and strong postal cancellation give it a classic colonial-era character. Used inverted overprints are particularly collectible because many were quickly withdrawn or printed in limited numbers.