Why is the sex ratio in Asian urban areas remains male-dominated?

In the urban areas of the Asian countries like Nepal, Pakistan and India the sex ratio is male-dominated. It is mainly because of the prevalence of male migration from rural areas to urban areas. The migration of female is comparatively less as their contribution to farming activity in the rural area is high. Also, the absence of housing facilities, the high cost of living, lack of employment opportunities and lack of safety and security in cities are the major reasons why the migration of women to urban areas is lower. Thus the urban areas remain largely male-dominated.