The 98-year-old was admitted to Asha Parekh hospital in suburban Santacruz on Aug 16.
"He is in the ICU...he is not on a ventilator. But he is on oxygen mask. His condition has worsened today," Hangal's son, Vijay, told PTI.
The doctors have told the family that he is in a critical condition.
Hangal slipped and fell down in his bathroom on Aug 13, fracturing his right femur (thigh) bone. Later, when he was to undergo surgery, it was observed that he has several complications from chest problem to breathing.
The yesteryear actor who has acted in over 200 films is best known for character oriented roles in films like Namak Haram, Sholay, Shaukeen, Aaina, Bawarchi and others.
Recently, he returned to face the studio lights after seven long years for TV Series Madhubala.