The universal measure of loudness is called decibel, usually abbreviated as dB. Zero decibel is the threshold of the hearing, while 85 dB is usually considered loud enough to cause damage to the ear.


It is the ratio of persons, households or volume of building or development to some unit of land area.

Density on Concentration

It is the number of vehicles occupying a given length of lane or roadway, averaged over time.


The arrangement of elements that make up a work of art, a machine or other man-made object; the process of selecting the means and contriving the elements, steps and procedures for predicting what1790 will be adequate to satisfy some needs.

Development Controls

It is process through which development carried out by many agencies, both by public and private are checked in the benefit of whole society.

Development Plan

To prepare a comprehensive development plan for urban areas, peri-urban areas under control of development authority/ Metropolitan planning committee.

DhalaoA premise used for collection of garbage for its onward transport to disposal site.


 a) On the scale of molecules, diffusion is a mixing of substances caused by molecular motion ( Molecular Diffusion). 

b) In atmosphere it implies the spread of pollutants by turbulence or eddy motion ( also called Atmospheric Diffusion )

Digital Elevation Model (DEM)

 A regularly spaces matrix of elevation values, which contain 3D information in a 2D digital format. It is represented as a 256 color grayscale image, where the grey level is proportional to the height of the building. 

Direct Use Value

 Economic values derived from direct use or interaction with a biological resource or resource system.


 Dispersion -The method by which a pollutant spreads from its point of emission and becomes diluted in the atmosphere. It includes transport by winds and simultaneous spread by turbulence (atmospheric diffusion).

District Road

District roads are the roads transferring each district, serving area of production and markets and connecting to these with each other or national or state highways.


Diverted Traffic

Traffic, which has changed from its previous route of travel to another route, without change in origin or destination


Domestic Biodiversity

The genetic variation existing among the species, breeds, cultivars and individuals of animal, plant and microbial species that have been domesticated, often including their immediate wild relatives.

Drainage BasinA geographical area bounded by a watershed and drained by a discreet drainage network


Drainage DensityThe total stream channel length per unit land surface area, normally calculated for an entire drainage basin.


Drainage Network

More or less synonymous with the channel network but may also include rills, gullies and larger underground pipes not considered part of a permanent surface channel network.


Drainage patternThe geometric configuration or plan of drainage network which usually reflects catchment geology, tectonic and denudation history.

Driving Rain Index

 It Characterises a given location and expresses the degree of exposure. It is the product of annual rainfall(in mm) and the annual average wind velocity (in metres per second, m/s).  

Dwell Time

The time for which a transit vehicle is stopped for the purpose of serving passengers (for example, stoppage of a bus for boarding and alighting of passengers.

Dwell Time

The time for which a transit vehicle is stopped for the purpose of serving passengers (for example, stoppage of a bus for boarding and alighting of passengers.


Dwelling Type

The physical arrangement of dwelling units includes: 1. Detached - Individual dwelling unit, separated from the other. 2. Semi-detached - Two dwelling units sharing a common wall. 3. Row / Group - Dwelling units grouped together linearly or in cluster. 4. Walk-up - Dwelling units grouped in two to five stories with stairs for vertical circulation. 5. High Rise - Dwelling units in five or more stories with stairs and lifts for vertical circulation.

Dwelling Unit

A general, global designation of a building / shelter in which people live. A dwelling may contain one more dwelling units.


Dwelling Unit Area

The dwelling unit area (sq. m) is the built-up, covered area of a dwelling unit.


Dwelling Unit Area

The dwelling unit area is the built-up covered area of a dwelling unit.

Dwelling units

In relation to a building or portion of a building, means a unit of accommodation, in such building or portion used sole for the purpose of residence.