Dutch households receive cannabis scented sniff cards

About 30,000 Dutch households are to receive marijuana-scented scratch cards in an effort to uncover illegal urban cannabis plantations. The scratch cards will be distributed in Rotterdam and The Hague.

The cards are being distributed so people can be aware of the smell of cannabis in order to ring a special number to report suspected growers.

The green scratch card reads: "Assist in combatting cannabis plantations."

The card lists other indicators of cannabis cultivation in suburban houses, including the buzzing sound of ventilators, suspicious connections to electricity supply points and curtains that are kept closed.

Citizens in Holland are generally allowed to grow up to five marijuana plants for personal use, but larger plantations have been springing up in suburban areas.

Authorities estimate there are about 40,000 illegal cannabis plantations in the Netherlands hidden away in attics, apartments and warehouses.