Zoroastrianism is a very ecologically aware religion, which has led to some commentators calling it the first Green movement.

In the Gathas, there are several references to Mother Earth and the wonders of natural phenomena such as the moon, the stars, the wind and so on.

Nature, in fact, is central to the practice of Zoroastrianism and understanding the interdependence of human life, the seasons and the elements lie at its core.

Many important Zoroastrian annual festivals are in celebration of nature: New Year celebration of Nowruz on the first day of spring (March 21); the water festival in summer; the autumn harvest festival of Mehrgan at the end of the season; and the midwinter fire festival.

It should be said that there are many days for feasting and celebrations to break up an otherwise laborious lifestyle and Zoroastrians traditionally sing, dance, play music and drink wine together during the celebrations, in marked contrast to those around them.

All Zoroastrian religious ceremonies at which priests officiate require the preparation of sprouting green shoots, fresh seed-bearing fruits such as watermelon and pomegranates, a tray of 7 dried fruits and nuts (lork), the presence of water, some bread, fire urn and a vase of flowers and evergreen branches, all laid out on a white cloth.

The Nowruz spread is a little more elaborate representing the provision by nature of all the life-enhancing produce that gives us pleasure in life and sustains us.

Zoroastrian doctrine requires people to act, for ultimately it is deeds which speak louder than thoughts and words.

It is felt that in order to be able to make sound judgements leading to action, a healthy environment is needed, so good order or Asha is to be observed with reference to the earth, the water and the air.

The requirement of non-pollution of these elements explains how the misunderstood funeral rite of exposure on mountaintops developed – the earth being viewed as a progenitor of life-sustaining food and not a place for dead bodies.

The mountaintop disposal could even be seen as a precursor to recycling through organ donation.

It also explains why Zoroastrians chose not to wash in rivers or streams but to draw water off in vessels to be used elsewhere so that the flowing water, which could be used downstream, would not be sullied by personal washing.

Much importance is attached to the meritorious act of making infertile land abundant by bringing water to it and making swampy, waterlogged land fertile by draining it and planting crops.

This environmental consciousness, which pervades the religion, accounts for the reputation Zoroastrians built up as excellent gardeners who knew how to irrigate in difficult conditions and how to produce abundance where others failed.

Exhortations to a marrying couple include several about the desirability of cultivating land and at the birth of each child, it is normal to plant a tree as it is at death.

Within a healthy and well-nurtured society, deeds above all else have to reflect the choice made by individuals in following the path of Asha.

Bodily cleanliness is, therefore, one manifestation of this and the wearing of the white muslin undergarment, the "Sedreh", donned at the initiation ceremony of "Sedreh Pushi/Navjote", represents this, as it reflects purity and has to be worn spotless.