My employer in Kolkata has not paid my salary for 4 months what legal action can I take

You can file a complaint before the Labor Commissioner in Kolkata under the Payment of Wages Act for non-payment of salary. Under West Bengal Premises Tenancy Act 1997 and the Industrial Disputes Act, you can also raise an industrial dispute before the Labor Court in West Bengal for recovery of unpaid wages. The Labor Commissioner can order the employer to pay the pending salary with damages. If you are a workman, you can approach the Labor Court directly, and if you are in a supervisory role, you can file a civil suit for recovery. If the authorities do not act, you can approach the Calcutta High Court under West Bengal Premises Tenancy Act 1997 for a writ of mandamus.