B737-900 Captain reported a dual bleed caution during take off. Crew rejected take off and returned to departure gate without incident.

Narrative

During the takeoff roll on Runway XX at ZZZ; at approximately 70 KIAS; the MASTER CAUTION illuminated with an AIR COND annunciation and DUAL BLEED light.The takeoff was immediately rejected. The Captain called 'REJECT;' retarded thrust levers to idle; deployed speedbrakes; and applied manual braking as required to maintain centerline control. No reverse thrust was necessary due to low speed and runway length available.A PA announcement was made immediately (Remain seated; remain seated") to secure the cabin. The crew notified ZZZ Tower of the rejected takeoff and advised that the aircraft would remain on the runway until completion of the Rejected Takeoff checklist and associated non-normal procedures.Tower acknowledged and coordinated accordingly.The Rejected Takeoff checklist was completed on the runway per QRH/Manual. Brake energy was assessed using the Brake Cooling Chart; energy level remained well within the safety zone (no fire hazard; no evacuation required).After clearance from Tower; the aircraft was taxied to a safe area (designated by Ground Control) to accomplish the Dual Bleed non-normal checklist. The procedure was completed without further abnormality.Two Electronic Logbook (ELB) entries were made:Dual Bleed caution during takeoff roll.Rejected takeoff performed at low speed.Contact was established with Maintenance Control. After consultation and agreement; a return to the gate was elected for further maintenance inspection and troubleshooting of the pneumatic/bleed air system. ZZZ Operations assigned Gate XX.The aircraft taxied to the gate without incident. No injuries to passengers or crew. No evacuation required. Passenger handling and communications were managed per company policy during the return."