A young boy's been airlifted to hospital after an incident in Pontardawe on Tuesday morning.
An 11 year old male occupant of a Vauxhall Corsa, received serious injuries.
One man's been arrested following the collision which involved six cars and an empty coach.
The A4067 was closed in both directions between Glais and Pontardawe for a number of hours, to allow for vital investigative work to be carried out.
South Wales Police would like to speak to any witnesses, who may have left the scene, prior to giving their details to officers, and anyone who may have dash-cam footage of the collision, or of any of the vehicles involved prior to the collision. Anyone with any such information, is asked to contact the Serious Collision Investigation Unit, via 101, quoting reference 1900200890.