Why in India some people don't cut their hair and wear a turban?
Sites dedicated to Sikhism explain that hair is a gift from God and therefore you don’t alter it (1). Moreover hair is beautiful (as any gift from God) then the longer the more beautiful.
That said, I am more and more convinced that any tradition or belief has a practical origin. As a matter of fact, if the Sikh religion appeared in 1469, emerging from the dominant religions (Hinduism and Islam), it is only in 1699 that cutting hair was forbidden (2). Now it so happens that at that time Sikhs were cornered: they had to give up non-violence (a founding principle of this religion) and take up arms against the Muslims who persecuted them (just as they were forcing Hindus to convert). As the Muslims wore beards – also certainly for practical reasons: “Act against the polytheists,” said Muhammad. “Carefully size your moustache and let yourself grow a beard.”(3) – and Hindus were moustachioed. To differentiate themselves (on the battle ground and otherwise) they had only two options left: leave it all or cut it all (but then it’s a lot of maintenance)...
And why the turban?
Long hair may be beautiful but it is not practical. Especially you are fighting and everything. Therefore, “the turban is in all respects a very convenient headgear; it is even more advantageous during war that our hats, because what they fall less easily, and can more easily prepare a blow of cutting edge”. (4) In addition it protects hair from the dust. And women can manage however they want (without a turban)...
But you must know that all turbaned men in India are not necessarily Sikh.
For example, the Rajasthani (top right) people, originally farmers and shepherds living in a mostly desert region, protect their head with a turban. Which varies in shape, size (even if it is usually 8-9 meter long (5)), material, colour and designs according to the wealth, caste and region of the wearer or the occasion.
Men wear turbans during weddings (top left).
And many janitors in big hotels or restaurants servers wear a turban (bottom left). In my opinion this practice dates from the colonial time when the Britishers must have found it classy to dress up their servants like that...
Morality, the turban does not (only) make the Sikh!
Subsidiary questions: How do Sikhs manage at the swimming pool with their turbans? How can Sikhs wear a helmet when on a bike? How do Sikhs pass airport security with their kirpan (dagger (2))?
At the pool, they take off their turbans but keep the piece of cloth that covers their hair and makes them look like Smurfs and they avoid putting their head under water. Same thing when they play any sport.
The regulation regarding helmet-wearing in India is a bit complicated, since it varies from one State to another. In Delhi for example, it is not compulsory for women to wear a helmet! And in Punjab and Haryana where there is a majority of Sikhs, wearing a helmet is simply optional. As a rule, Sikhs are not forced to wear helmets (which are too small to accommodate the turban!).
The Constitution of 1971 permits Sikhs to carry the kirpan in India. As for air-traveling, the kirpan is only allowed in a check-in luggage!
And why do all Sikhs bear the name Singh (men) and Kaur (women)?
Sikhism is an egalitarian religion, condemning discrimination based on gender or caste. Since in India, family names refer to caste, religion, region of origin, profession (yes all this! and it's hyper-complicated!), Sikhs use their ‘middle name’ as a surname. ‘Lion’ for men (Singh) and ‘Princess’ for women (Kaur).
But beware, the name Singh does not (only) make the Sikh.
There are people by the name Singh that are not Sikh. How to make things simple when they can be complicated? J
(2) Guru Gobind Singh (last of the 10 gurus who have developed the Sikh doctrine) has imposed the 5 kakas (5 K): hair and beard never cut (kesh) and retained by a comb (Adriana) symbolizing neatness, a metal bracelet (kara), military breeches (kachha) and a dagger (kirpan). Source: http://www.thecanadianencyclopedia.com/articles/fr/sikhisme; http://www.lemondedesreligions.fr/archives/2006/03/01/XVe-siecle-gourou-Nanak, 7928403.php
(4) http://alembert.fr/index.php?option=com_content & id = 640409723
Other sources: http://forums.Bharat-rakshak.com/viewtopic.php?p=600509 ; http://www.fashion.arts.AC.UK/media/research/documents/toolika-Gupta-effect-of-British-Raj-on-Indian-costume.PDF