<p>Air pollution in Indian cities, particularly Delhi, the capital of India and one of the most polluted mega-cities in the world, has become a critical issue in recent years. Besides its adverse effects on human health, particulate matter contributes to reduced solar energy production by accumulating on solar panel surfaces and lowering energy transmittance. To assess the impact of dust on solar panel efficiency, a 300-day outdoor experiment was conducted in Delhi, starting in November 2022. The study found that weekly cleaning of solar panels resulted in a 7.6% increase in energy output compared to panels cleaned naturally. Rainfall significantly improved air quality, thereby reducing soiling loss. The study also explored the optimal cleaning intervals for solar panels, offering valuable insights for developing efficient cleaning schedules based on Delhi’s pollution levels. From November 2022 to August 2023, soiling rates were highest in winter, particularly in January, and lowest during the rainy season in July. The average soiling loss was 7.6% per month, equating to a daily loss of 0.25%. Scanning electron microscope imaging analysis revealed a high concentration of PM2.5 particles, corroborated by the Central Pollution Control Board data, identifying PM2.5 as a major pollutant in Delhi. X-ray fluorescence analysis showed that the dust particles primarily consisted of oxygen, silicon, sodium and calcium. This research will aid in designing effective cleaning strategies and schedules for solar panels in polluted areas, benefiting solar photovoltaic systems.</p>