Covid-19 pandemic affected aviation severely, resulting in unprecedented reduction of air traffic. While aviationis slowly re-gaining traffic volumes, we use the opportunity to study the arrival performance in the Terminal Maneuvering Area (TMA) in non-congested scenarios. Applying flight efficiency and environmental performance indicators (PIs) to the historical data of arrivals to Stockholm Arlanda airport, we discover noticeable inefficiencies, despite significant reduction of traffic intensity. We analyse the impact of such factors as weather and traffic intensity on arrival efficiency in isolated scenarios when only one factor dominates. Our analysis uncovers that weather has a stronger influence than congestion on vertical efficiency, while congestion affects both, but mostly lateral efficiency.