Fad attire of the mid-1960's, it's one of the easiest-to-caracature artifacts of the Peacock Revolution, now found in any number of hideously garish colors and/or fabrics. In truth, however, a Nehru outfit can be one of the most graceful and dignified alternatives to the suit-and-tie look, and when carried out in its original spirit, is one of the most attractive and wearable menswear looks around.

First, the jacket itself: a band collared and hip-length closely-fitting coat favored by Jawaharlal Nehru, and adopted by intellectuals in the Northeastern United States after his death, who influenced Mods, Hippies, and well, just about everyone. Exotic in origin, Nehru looks appealed to the mid-decade's taste for simplicity and ease (no lapels, no collar, no breast pocket, no shirt buttons, and, with synthetic-fiber Sansabelt pants, no belt or ironing) and its flair for individualistic ornamentation (as you'll soon see).
Nehru's own Nehru was white, and Austin Powers' were in a variety of hues, but for a truly retro experience, it should be in a classic men's suiting color -- navy blue, for instance. It should be paired with a similarly classic pair of pants -- chinos or brown tweed are just about right, and a white (or for the more adventurous) black turtleneck sweater. (I introduce the concept of colored shirts -- but only in classic Northeastern colors -- at your own risk.) Since there's no place to put a tie, the resulting expanse of chest can be ornamented in several ways, which mark the Nehru outfit with its distinctive stamp.

First, there is the most formal and classic ornament: a string of amber mala, crossed once, with the tassel in the front, and worn with the respect due such a religious symbol. Rosary beads make a good contemporary equivalent.
Coming down from this, an Hermes or Pucci scarf is not too bad, either, worn loosely as an anti-tie. A medallion or symbol of some kind: an Iron Cross taken as war booty, any military decoration, either antique or personal, a large coin, mounted as a charm, etc., or a zodiac sign can also be quite dashing, especially if there's some significance or story behind it.
On the sleazier side, you can always wear a medallion in plastic, Mardi Gras throws, or simply plain colored beads (love beads)...but this is beyond the scope of this WU.
Shoes: Loafers, either Bass or Gucci, and no socks. There really is no substitute, although well-crafted tennis or yachting shoes work just as well. Sandals should be neat-looking, and worn with socks.
Belt: Either a standard Coach brass-and-leather, or a hand-crafted alternative...a good buckle can really make this outfit! You can also wear Sansabelt pants with this, which don't need one -- very in period, but only to offset some other detail -- you can be too minimalist, too!
Hair: Try for a gently lengthened version of standard men's styles, rather than a whole mane. Bangs are excellent.
Accessories: Some rings (plural), gradient sunglasses or photogreys, and a camera bag go very well with this....as does a camera, a blonde, and a fast foreign car!

Enjoy your Nehru!