Hindi.
You must've seen news18 rajasthan, news18 Bihar. This state's local language is rajastani & bhojpuri respectively. They're still using hindi languages. Such channels are meant for giving news of that particular state in hindi.
Also most of people residing here knows Hindi well unlike south Indian channels where most of people are not aware of hindi. Thus they tend to give news in this particular language i.e tamil, telugu, kannada & malayalam.
@Shantanu bro.Bhojpuri is not used across Bihar.There are other languages like Maithli.Hindi is widespread used.People mostly uses local dialect within FnF.
Though News18 Urdu is already there for Urdu, it has to cover not only J&K but also Hyderabad. News18 J&K may be something like Gulistan News (50% Hindi, 50% Urdu).