What does the term ‘reverse migration’ refer to?

Read the given passage and answer the questions that follow.

Residents of Bhavanpur, a village about 15 km outside Ahmedabad, have been protesting against their inclusion in the city’s urban area by the local urban development authority. Similar protests have been observed in villages elsewhere in Gujarat. It’s a strange trend, the fruits of urban development seemingly rejected. Meanwhile, pollution in India’s urban areas seems to have sparked off a reverse migration. Farmers from Haryana who had migrated to Delhi and Gurugram for work to escape an agricultural crisis are increasingly going back to their farms during winter, unable to take the toxic pollution. And it’s not just big cities. India’s urbanisation template is clearly ripe for change. Over 34% of India’s current population lives in urban areas, rising by 3% since 2011. More importantly, while existing large urban agglomerations (those with a population above 50 lakh) have remained mostly constant in number since 2005, smaller clusters have risen significantly (from 34 to 50 clusters with 10-50 lakh population). By some estimates, India’s urban population could increase to 814 million by 2050. And yet, cities look and feel downtrodden, driven with poverty and poor infrastructure, with little semblance of urban planning. With an increase in urban population will come rising demands for basic services such as clean water, public transportation, sewage treatment and housing.