Nearly half the families in and around New Delhi have sought medical help for respiratory ailments connected to severe pollution engulfing India’s capital, according to a new survey.

About 81% of respondents to a questionnaire by the pollster LocalCircles reported that one or more family members are experiencing an illness connected with exposure to toxic air. Four out of ten households consulted a doctor. Answering a separate question, half of the participants said that in the past three weeks they have bought medicines or devices.

The survey results underscore the risks that environmental degradation poses for Prime Minister Narendra Modi’s administration as it seeks to expand the economy in the world’s most populous nation.

— Bloomberg