they are still telecasting in 4:3 because many people still have 4:3 conventional TV screens....only a minority has HDTVs (these have 16:9 aspect ratio)....on HDTVs, 4:3 videos will be sandwiched between black bars....some HDTVs have a button on the remote which will fully fit the 4:3 videos to the screen....it's called 'wide', 'zoom' etc by different brands....but this is actually modifying the picture by stretching, cropping etc....i myself don't like to use this function on the tv.....i just watch it with the black bars....then i can be sure that i am seeing the original picture.
even youtube display area is 16:9....only manorama news is sandwiched....others are filling the area.