**2.3 Essential oils**

Essential oils from plants are widely used in pharmaceuticals, cosmetics, perfumery and specialty applications in various industries. The value of essential oil bearing crops can be augmented by utilization of wastes using facile and economic methods. The major essential oil bearing crops are lemon grass, mentha, eucalyptus, lavender, rose, geranium, rosemary, basil, thyme, peppermint, chamomile, etc. [5].
