On *A the following airlines fly to Chennai (Madras)
SQ from SIN
TG from BKK and DXB
LH from FRA

On OW the following airlines fly to Chennai
BA from LHR

So a One World Explorer would require a surface segment (cant do LHR-MAA-LHR), while a *A RTW there are several options (plenty of flights from SIN/BKK to HKG).

Since Mumbai is mentioned as well, here are the *A flights to Mumbai
TG from BKK
LH from FRA
SQ from SIN

and OW flights to Mumbai
CX from HKG via BKK
CX from DXB
BA from LHR
QF from SYD