“Eastern China’s clear and dry start to 2025 has continued through April, maintaining the strong irradiance anomalies first observed in January. Solar irradiance across the eastern lowlands remains markedly elevated, supported by persistently weak onshore trade winds and a notable reduction in atmospheric haze. These conditions, which follow an exceptional January, have pushed year-to-date irradiance in some parts of China to levels 30% above the long-term average…

A key factor behind this trend is the significant reduction in airborne pollutants. From January through April, as measured by aerosol load, major Chinese cities recorded some of their cleanest air in nearly two decades. Irradiance lost to aerosols and haze was at its lowest level since Solcast tracking begins in 2007 in Beijing, and second lowest in Guangzhou. Shanghai’s readings were the fourth cleanest on record, trailing only the pandemic-influenced years of 2020–2022. Seoul, too, saw its lowest levels of pollution over the same period.”

From pv magazine.