The national capital grappled with 'poor' air quality on Saturday as the Air Quality Index (AQI) reached 231 at 9 am. The minimum temperature for the day settled at 20.9 degrees Celsius, slightly below the season's average. The deteriorating air quality prompted the Commission for Air Quality Management (CAQM) to invoke Stage-I of the Graded Response Action Plan (GRAP) throughout the entire National Capital Region (NCR).