Yes..When you need to transmit to 3 Kms max, yu'll need more power on any frequency,and the Wireless Planning and co-ordination wing of the Govt of India Rules permits any transmission only upto 500 milliwatt only for educational purposes, which may not be continuous and which should carry the identification of the transmitting station. In case you need more power, you need to submit your proposal to the said dept and get a valid License on a assigned frequency by the dept where you may use your transmissions below the permitted power limits. naturally the license will come for a yearly fee. Visit the WPC website for detailed rules, regulations and other related doccuments.
**broken link removed**
Cheers