EIA Studies of 3 Pre-Identified Hazardous Waste Disposal Sites in ...

Rapid EIA Studies of 3 Pre-identified Hazardous Waste Disposal Sites in NCT - Delhi:
4.7 METEOROLOGY
Page No.95
4.7.1 Climate
The climate of NCT, Delhi is mainly semi-arid and is largely influenced by its inland
position and the prevalence of air of the continental type during the major part of the
year. Extreme dryness with an intensely hot summer and cold winter are the
characteristics of the climate. Only during the three monsoon months July, August
and September does air of oceanic origin penetrate to this district and causes
increased humidity, cloudiness and precipitation. The year can broadly be divided
into four seasons. The cold season starts in late November and extends to about the
beginning of March. This is followed by hot season which lasts till about the end of
June when the monsoon arrives over the district. The monsoon arrives over the
district. The dryness of the air with an intensely hot summer and a cold winter are
the characteristics of the climate. Air of oceanic origin reaches the city only during
the three monsoon months, July, August and September, bringing with it increased
humidity, cloudiness and rain. The year may be divided into four seasons. The cold
season starts in late November and extends to the beginning of March. This is
followed by the hot season which lasts till about the end of June when the monsoon
arrives over the region. The monsoon continues to the last week of September. The
two post monsoon months October and November constitute a transition period from
the monsoon to winter conditions.
4.7.2 Rainfall
The rainfall within NCT - Delhi are being recorded at 13 stations:
1. Chandrawl (obsy) 2. New Delhi (Safd) 3. New Delhi (Palam)
4. Okhala (obsy) 5. Mehrauli 6. Delhi (Sadar)
7. Nangloi 8. Sahadara 9. Najafgarh
10. Badli 11. Alipur 12. Narela
13. Delhi (city)
The normal annual rainfall in the NCT -Delhi is 797.3 mm (50 years). During the
period 1993 - 1997, annual average rainfall observed was 905.32 mm. About 81% of
the annual rainfall is received during three monsoon months of july, August and
September, while balance annual rainfall is received as winter rains and as
thunderstorm rain during pre and post-monsoon months. There have been a steady
change in rainfall from year to year. The maximum rainfall recorded in the region was
251% of the normal in 1933 while 44% of normal was the minimum in 1951. A study
of the trend of the annual rainfall in the region for 80 years (1901 - 1980) shows that
precipitation is mostly erratic in its arial distribution and intensity. The rainfall
increases from South west to north east.
On average, rains of 2.5 mm or more falls on 27 days in a year. Of these, 19 days
are covered under monsoon months; two to three days in June while rest in other
seasons.
Environment Division, National Productivity Council, New Delhi
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