Bulgaria ranks 30th in the 2018 Environmental Performance Index, but scores low on air quality. Particulate levels are the highest in Europe, especially in urban areas affected by automobile traffic and coal-based power stations. One of these, the lignite-fired Maritsa Iztok-2 station, is causing the highest damage to health and the environment in the European Union. Pesticide use in agriculture and antiquated industrial sewage systems produce extensive soil and water pollution. Water quality began to improve in 1998 and has maintained a trend of moderate improvement. Over 75% of surface rivers meet European standards for good quality.