aeronautical mobile service is geographically divided between 14 MWARA (major world air routes areas, and about 60 RDARA (regional and domestic air routes areas).
The Indian subcontinent is included in the MID (Middle East) and EA
(Eastern Asia) and INO (Indian Ocean) MWARAs and 4 different RDARAs.
A number of HF
band segments (eg. 5450 to 5680KHz) are dedicated to the aeronautical service (worlwide), and in each of these a number of frequencies are allocated to the specific MWARA and RDARA. (eg. MID: 5658 and 5667KHz)
Each country has one or more ATCenters monitoring the frequencies in its particular MWARA and/or RDARA zones. (eg. Mumbai)
So, assuming you have a receiver with a sufficient "memory" bank (a "must"), you can store a large number of these frequencies for your own and other MWARA and RDARA, and consequently let your receiver scan them.
So far so good.
The problem starts when one realizes that the propagation of radio waves in the HF
spectrum is subject to a lot of variable factors, and that each "part" or segment has its own specific behaviour.(eg: the 5MHz band behaves totally differently than the 13MHz band)
The said factors include: solar activity, season, time of day/night at yopur location and at the trasmitting station location, atmospheric phenomenons, geomagnetic particularities,...and a few others without forgetting your own receiver and antenna characteristics.
Though, in theory at least, at any particular time you might be able to listen to an ATC or aircraft on (at least) one of the allocated bands, even at your antipode (Mexico ?).
eg. in the (your) late evening, you will (typically) be able to pick up traffic from your own and contiguous MWARAs (Africa, SE
Asia, N central Asia) in the 5, 6, 8, 10 and 11MHz bands. Around sunrise you might pick up signals from very far away on the 13 and 17MHz bands.
Seems fine, but remember that pilots' aim is to contact the relevant ATC, not necessarily to be heard by a radio enthusiast in India.
They will use a band which is appropriate according to their own distance to the ATC and time of day, if this corresponds to your own "window" you will hear them.
traffic between a/c and ATC is usually limited to a short "waypoint" or "position" report.
Drop me an e-mail if you wish to know more.