New Delhi, July 16 -- Delhi breathed its cleanest air in nearly two years on Tuesday, as it clocked a "good" air quality index (AQI) for several hours in the morning and afternoon, before dipping to the "satisfactory" range by the evening. The 24-hour average AQI was 51 ("satisfactory"), according to the Central Pollution Control Board's daily bulletin, the best air it had breathed since it recorded an AQI of 45 ("good") on September 10, 2023. To be sure, the CPCB classifies an AQI between 0 and 50 as "good", between 51 and 100 as "satisfactory", between 101 and 200 as "moderate", between 201 and 300 as "poor", between 301 and 400 as "very poor", and over 400 as "severe". Delhi's 24-hour rolling AQI was 48 at 10am on Tuesday, according to CPCB data. It dipped to 49 ("good") at noon and touched 50 at 3pm, before slipping to a "satisfactory" AQI of 51 at 4pm. Experts said favourable meteorological conditions were behind this improved air, which included consistent rainfall and good wind speed. "We're seeing on-and-off rain every few hours over Delhi and similarly consistent winds that are allowing dispersion of pollutants. At the same time, rain is being recorded in neighbouring NCR too, which is once again having a positive impact on the air here," said Mahesh Palawat, vice president at Skymet. He said that if rainfall was not widespread enough, the AQI would not have dipped so low. Delhi usually breathes its cleanest air in the monsoon. Historically, all or most of the "good" air days were recorded between July and September. Last year, the lowest AQI was 52 ("satisfactory"), recorded on September 13. In 2023, only a single "good" air day was recorded. In 2022, Delhi had three such days; 2021 had one; 2020 had five due to the Covid-19 lockdown. There were two good air days each in 2019 and 2017. Officially, Delhi is yet to record a "good" air day this year, as only the 4pm bulletin is considered for long-period data. Delhi recorded light to moderate spells of rainfall on Monday, with Safdarjung, the city's base station, receiving 10.2mm of rainfall in the 24 hours till 8.30am on Tuesday. During the same period, the Palam observatory recorded 28.2mm of rainfall, Lodhi Road 10.2mm, Ayanagar 31.2mm, Ridge 6.4mm, Rajghat 5.4mm, Pusa 12mm, Najafgarh 17.5mm and Mayur Vihar 3mm. Only scattered rainfall was recorded on Tuesday. Until 5.30pm, the Safdarjung station recorded no rain, while "trace" rainfall was recorded at the Lodhi Road and Ayanagar stations. The Mungeshpur station, meanwhile, recorded 0.5mm of rainfall, and Mayur Vihar recorded 1mm. So far, the city has logged 98.4mm of rainfall in the month of July. The normal monthly average is 209.7mm. Although no colour-coded alerts are in place till next Monday, the India Meteorological Department (IMD) has forecast rainfall to continue. Light to moderate showers are likely on Wednesday, with mostly scattered light rainfall from Thursday to Monday, it said. The maximum temperature on Tuesday was 33.9degC, which was a degree below normal. The minimum temperature was 24.5degC, which was three notches below normal. The maximum temperature is forecast to hover between 31degC and 33degC on Wednesday, while the minimum temperature is likely to be between 23degC and 25degC, according to IMD. Forecasts by the Centre's Air Quality Early Warning System (AQEWS) for Delhi forecasted the AQI to stay "satisfactory" till at least July 18, with it possibly dipping to "moderate" in the subsequent six days....