IPTV has no connection to broadband speeds.
Of course it has. IPTV needs live streaming video to flow and certain QoS needs to be met. Among those QoS parameters average download rate is also important. If the download rate for the specified compression format cannot be met, the quality of the video suffers, frames will be dropped. HD requires higher bitrate.
16 Mbps is the bandwidth allocated till the Airtel network. IPTV transfers also happens with this bandwidth and hence it has connection.