In congested areas toilets can be build using the technology followed in flights. Instead of flushing with water air can be used, that save water and less sewage.

UDDT in Burkina Faso
Urine diversion refers to the separation of human urine from feces at the point source, i.e. at the toilet fixture or outhouse. Separation of urine from feces allows human waste to be treated separately and used as a potential resource. Applications are typically found where connection to a sewer based sanitation system is not available or areas where water supplies are limited. A toilet used to facilitate the separation of human waste products is called a urine diversion

As temporary measure, we can create space, create septic tanks, etc., in urban congested areas to enhance sanitation quality, but if we have to create & maintain hygenic conditions on long term, we will require multi-pronged approach. Attached PDF discusses these points.

We need to build mobile toilet with payment systems and also proper maintenance and financial set up to maintain these toilet. Every urban area we need to find houses with out toilet and people given awareness about hygiene and cleaniless.

The Last one- Composting Toilets for small lands may be a possible solution for it

Rural Sanitation Method.

Sanitary latrines occupying very less space can be built in just a space of 1m*1m space, where a latrine can be built, a tank for water supply can be built on the roof of the toilet connected to the two taps. One tap would be at basin & the other for cleaning latrine, a bucket would be placed below the tap, the bucket can be attached to the wall by a wire or a rope so that it can't be taken away. A huge concrete pit can be constructed just below & an outlet must be outside to evacuate periodical

This the problem in old part of city like chauk area where the width of street is 4 to five feet. Where sewerege system can not be develop.these can be seen at a large system in varansi in the constituency of pm. In these street human excreta is being head leaded in open looks very inhumatrian.few design are available in iit roorkee.a team of roorkee shall be deployed with details survey and their disposal in varansi.my self being a civil engineer eager to give my service for this social work

Compositing toilets are suitable alternative.They work on the principle of aerobic decomposition.It is aspecial toilet designed to process waste into smaller harmless and non-offensive compost smells like garden soil.Human waste is 90% water.The primary goal of composting is evaporation of water which is done with the help of heating element/fan.Rest Solid part is store in a special drum inside the toilet.Solid waste is aerated and broken into smaller parts.

1.Identify those conjusted areas with insanitary toilets
2.Study the population and number of houses
3.Prepare an estimate of toilets reqiured
4.Allow PPP model in toilet constructions
5.Construct Composting toilets.