Pushkala and Taksha were the sons of Bharat and Mandavi in Valmiki Ramayana. They were grandsons of Kaikeyi and great grandson of Ashwapati (father of Kaikeyi). In original Valmiki Ramayana, Kaikeya’s imperial palace was in Balkha (in modern day Afghanistan) but in Mahajanpada era, Kaikeya was in modern day Pakistani Punjab.
Bharat defeated Gandhara and the established two cities Pushkalavati and Takshashila and made his sons the Kings of the cities.
In Ananda Ramayana, Naga Princess Kalavati and Gandharva Princess Chanchala were married to Pushkala. Naga Princess Kalika and Gandharva Princess Chapla were married to Taksha.