According to DGCA Rule 63 you need a radio onboard to operate both VFR and IFR
63. Aircraft for which radio apparatus is obligatory-
(1). All aircraft registered in India and required to be operated in accordance with VFR/IFR condition shall be provided with communication equipment which
is capable of conducting two-way communication at all times with those
aeronautical stations and on those frequencies as prescribed by the
appropriate authority. The communication equipment so provided shall
be of a type approved by the airworthiness authority of the country of
manufacture of aircraft and acceptable to the Director General.
(2). An aircraft shall be provided with navigation equipment which will enable it to proceed :
(a) in accordance with the flight plan; and
(b) in accordance with the requirement of air traffic services, except
when, if not so precluded by the appropriate authority, navigation for
flights under the visual flight rules is accomplished by visual
reference to landmarks at least every 110 kms (60 Nautical Miles).
DGCA Rule 9 also adds some stipulations to the operation of the radio its self
9. Radio-telegraph apparatus -
(1) No person shall operate radio transmitting apparatus in any aircraft registered in India unless he
holds a licence of the type required by the provisions of Part V in
respect of aircraft required by these rules to carry radio-telegraph
or radio-telephone apparatus, as the case may be, and issued in
accordance with those provisions.
(2) Radio-transmitting apparatus carried in aircraft shall be operated
under the conditions defined by the International Tele-communication
Convention (Madrid, 1932) and the general radio-communication
regulations annexed thereto as far as these apply and shall be
operated only during the hours in which such operation is permitted by
the Central Government.
(3) Aircraft registered in India and required by these rules to carry
radio-telegraph apparatus shall be fitted with such apparatus in
accordance with the provisions of Part VII.
(4) Nothing in this rule shall exempt any person from those provisions
of the Indian Telegraph Act, 1885, and the rules made thereunder which
require that radio-telegraph apparatus shall be licensed.
You can find the rest of the rules here. I went through them briefly and cant find a whole lot on certifying home built aircraft. Or what rules they would actually fly under. There is a short list of things related to actually getting an airworthiness cert here but it does not touch on VFR/IFR classifications related to that.
As for the safety aspect of it, that depends on your countries aviation infrastructure and if carrying a radio benefits you. If no one is listening on the other end then its not going to add much but weight to the aircraft. From a regulatory standpoint you may need it to enter certain airspaces (you may also need a transponder for that as well) I cant find a whole lot on the DGCA website about airspace regulations so its hard to say exactly when you would need one. I can only compare it to places I have flown and here in the US while you don't legally need a radio in uncontrolled airspace its still a good idea to have one and to use it as you should (CTAF announcements, flight following if you like, 121.5 if you need it etc.)