For the purpose of Customs clearance of arriving passengers, a two channel system has been adopted

• Green Channel for passengers not having any dutiable goods.
  
  
• Red Channel for passengers having dutiable goods.

However,

• All the passengers shall ensure to file correct declaration of their baggage.
  
  
• Green channel passengers must deposit the customs portion of the disembarkation card to the custom official at the gate before leaving the terminal.
  
  
• Declaration of foreign exchange/currency has be made before the custom officers in the following cases :
  
  
  • where the value of foreign currency notes exceed US $ 5000 or equivalent
    
    
  • where the aggregate value of foreign exchange including currency exceeds US $ 10,000 or equivalent

Passengers walking through the Green Channel with dutiable / prohibited goods are liable to prosecution/penalty and confiscation of goods.

Trafficking of Narcotics and Psychotropic substances is a serious offence and is punishable with imprisonment.

Reference Site
http://www.cbec.gov.in