This galaxy - located about nine billion light years away - emits powerful radio waves, the researchers found.
Such galaxies with extremely large 'radio size' are called giant radio galaxies.
"Our work presents a case study of a rare example of a GRG (giant radio galaxy) caught in dying phase in the distant universe," the researchers said.
This newly discovered galaxy known by its scientific identification 'J021659-044920' was discovered using the Giant Metrewave Radio Telescope (GMRT), an array of 30 fully steerable, 45-metre diameter antennas, spread out over a 30-km region around Khodad, near Narayangaon town of Pune district.
This project was led by Prathamesh Tamhane from the Indian Institute of Science Education and Research (IISER-Pune) working under the supervision of Yogesh Wadadekar at the National Centre for Radio Astrophysics.
While radio galaxies with size less than a million light years are common, giant radio galaxies are extremely rare, even more so, at large cosmic distances where only a handful have been discovered so far.
This newly discovered galaxy is the newest member of this elite group, the astronomers said.
The findings were detailed in the journal Monthly Notices of the Royal Astronomical Society.