What is the Gaganyaan mission?
The Indian Space Research Organisation (ISRO) plans to launch Gaganyaan in 2025 (the final date will announced in the future). This mission seeks to show human spaceflight capability. ISRO will send three people into space for three days before they safely return to Earth.
ISRO is working hard to develop all the technology needed for this mission, like a launch vehicle to take the crew to space, a crew life support system, and crew emergency escape systems.
ISRO will also do many tests before the real mission. They chose four pilots from the Indian Air Force (IAF) to be astronauts for this mission. You can find more about the Gaganyaan mission in these articles: Article 1, Article 2, and Article 3.
Recently, the names of the four astronauts, or vyomnauts, have been announced.

Who are the four astronauts selected for the Gaganyaan mission?

The four astronauts are Group Captain Prasanth Balakrishnan Nair, Group Captain Ajit Krishnan, Group Captain Angad Pratap, and Wing Commander Shubhanshu Shukla. Their names were announced at an event where Prime Minister Narendra Modi was present.
The astronauts have been training for space travel, first in Russia and then at ISRO's Astronaut Training Facility in Bengaluru. Out of the four, three will be chosen for the final mission.
Has any Indian travelled to space?
Rakesh Sharma was the first Indian to travel to space. He travelled on a Russian-built spacecraft in 1984. There have also been other Indian-origin astronauts who have travelled to space, like Kalpana Chawla.