Is it permissible for a woman to work in hair removal (halawa), as it is her sole source of income, given that she is obliged to see parts of the 'awrah, such as above the knee, and is this work considered haram?

Removing hair from the body is permissible for women. It is permissible for a woman to remove hair for another woman, provided that this does not entail seeing or touching the 'awrah (private parts). A woman herself must directly handle what is unlawful for others to see or touch of her 'awrah. Imam Ahmad permitted the use of al-nūrah (a depilatory substance) for hair removal, but with a warning that no one should see the 'awrah except for one's wife or slave woman.