Beijing is China's political, cultural, and educational centre and one of the most populous cities in the world. Its population in 2012 CE was c. 21 million; nearly 96 % are ethnic Han Chinese who constitute about 20 % of the entire global human population, making them the largest ethnic group in the world. There is considerable genetic, linguistic, cultural, and social diversity among the Han Chinese, mainly due to thousands of years of migration and assimilation of various regional ethnicities and tribes within China. They sometimes refer to themselves as Yan Huang Zisun, meaning "descendants of (the god-emperors) Yan and Huang". - Go to Beijing and prepare to be puzzled!
Street Portrait and Background
Always be aware of the background of your street portrait. The simpler the background, the easier it is to create a clear portrait. However, some street portraits might require you to include distinctive details of the background which can add meaning to the model and enhance the composition of your photo. You need to be sure that your background is working with your model.
(i) You can move your model out of a messy or meaningless background into a less messy and/or more meaningful background, or you can use the right aperture for either a sharp background or a blurred background to create the optimum depth of field: c. f/2.8 - f/4.0 for a blurred background and c. f/8.0 - f/16.0 for a sharper background, depending on your intention.
(ii) You should avoid (a) the proverbial tree growing from your model's head, (b) any strong "cutting" lines (e.g. the horizon line) behind your model's head, and (c) all kind of distracting features in the background such as any high contrasts and bright areas away from your model, any sign/text which doesn't belong to the model's world, and any intense colour (e.g. highly saturated red, orange, yellow) which competes for the viewer's eye.
(iii) You should be sure that people in the background don't look at the camera (even if they are out of focus), unless your intention is to shoot a double portrait.