A321 pilot reported during gate arrival they were abruptly stopped by ground personnel to avoid hitting a tug parked nearby. Pilot cited poor ramp lighting as contributing to the event.

Narrative

Arriving into ZZZ Gate XX local we approached the gate at 180 degree angle on a very dark and poorly lit ramp. Wing walkers and Guide-man in sight. As per sops extinguished non-essential lighting and advanced to gate parking. We were abruptly stopped by guide man; and complied. We look out and saw a small tug in front of our left engine. Strict adherence to SOPs and safety protocol trapped what would have resulted in aircraft damage on the ramp.Recommendations: The RAMP area needs an upgrade in lighting. Ramp personnel needs to ensure area is free of obstructions and equipment in the critical Area. Ramp exemption on company pages for regional carriers needs to be addressed.Cause: Clean ramp policy exemption. Extremely dark ramp area. Regional operator at adjacent gate FREQUENTLY leaves vehicles and equipment in [Gate] XX safety area. Multiple lead in lines. Aircraft parked on ramp taxiway line requiring attention to the left of aircraft immediately prior to 90 degree right turn into the gate.Suggestions: Air Carrier regional at adjacent gate needs to stop leaving vehicles and equipment in safety area! Gate XX needs to be properly lit. Overnight aircraft should not be parked on ramp taxiway line off the gate.