It keeps different social strata from mixing.

它可以防止不同的社会阶层混在一起。

Here, social strata refer to the different groups that make up a society.

在这里，社会阶层是指构成社会的不同群体。

At the highest social strata, you're exempted from military service, and more or less guaranteed a high status job.

在最高的社会阶层，你可以免除兵役，或多或少地保证了一份高地位的工作。

People of all ages, castes, and social strata come together to drench each other in a riot of hues, using powdered colors called 'gulal' and water-filled balloons.

各个年龄段、种姓和社会阶层的人们聚集在一起，使用称为“gulal”的粉末状颜料和装满水的气球，用五彩缤纷的色彩互相浸湿。