Cannabis scratch 'n' sniff cards handed out
About 30,000 Dutch households are to receive marijuana scratch cards to help them tell if their neighbours are growing the drug.
Authorities in Rotterdam and The Hague say are distributing the cards to help people recognise what cannabis smells like.
The cards also include a number to call to report suspected illegal marijuana-growing, reports the BBC.
Dutch authorities turn a blind eye to citizens growing up to five marijuana plants for personal use.
But they want to crack down on the estimated 40,000 bulk plantations hidden away in attics, apartments and warehouses in the Netherlands.
"Citizens must be alerted to the dangers they face as a result of these plantations, and if they become aware of any suspect situations they must report them," said spokesman for Arnie Loos.
The green scratch card, measuring 20cm by 10cm (8in by 4in) reads "Assist in combatting cannabis plantations."
When scratched, the card reveals its scent as well as a police number people can call if they suspect that a neighbour is growing marijuana on a large scale.
Dutch authorities say the plantations are a hazard which can cause fires or accidents because of the cables and lamps needed to maintain a cultivation temperature of 27C.