Search

Transboundary pollutant transport is considered as one of the primary factors causing the seasonal air quality deterioration in Delhi, India's capital. The highest standard deviations exceeding days in winter for NO2 (7.14–9.63%) and SO2 (4.04–7.42%) in 2019–2022 underscore the role of meteorological conditions in Delhi's pollution. In contrast, the post-monsoon season shows the highest pollutant exceedance days (4.52–8.00%) for CO due to stubble burning (SB) in Punjab (68,902 fires/year). Despite the government's assertions of decreasing SB events (14.68%), the city's CO exceedance days persistently rose by 6.36%. CAMS data is used for assessing contribution hotspots through back-trajectory analysis at multiple heights. An overlap hotspot of 111 sq. km area is identified in the Southeast parts of Punjab that have a higher contribution to the CO levels in Delhi during the post-monsoon season of 2019. Similarly, hotspots are also observed for SO2 over industrial areas of Punjab during the post-monsoon and pre-monsoon seasons. The same seasons show similar contributing patterns for NO2 highlighting the influence of consistent emission patterns and meteorological conditions. The clear delineation of hotspots using the receptor model at multiple heights coupled with source apportionment studies will assist decision-makers in addressing the pollution sources outside Delhi. [ABSTRACT FROM AUTHOR]

The study area Delhi is second most populous city and third largest urban area in the world. Though the area lies in seismic high damage risk zone, number of high rise building and construction of mega structure at several sites of the city increase rapidly. In this study field Standard Penetration Test (SPT) values of soil collected from 750 boreholes data were analyzed to identify liquefiable sub-surface soil layers. Finally, liquefaction susceptible sub-surface maps of the region at various depth (20 m, 15 m, 12 m, 9 m, 6 m and 3 m) from ground level is prepared. The outcome of this study will be useful input for preliminary foundation and designing of earthquake resistant high rise building and seismic microzonation studies of Delhi. [ABSTRACT FROM AUTHOR]

We present the first Multi-Axis-(MAX-) DOAS observations in India performed during April 2010 and January 2011 in Delhi and nearby regions. The MAX-DOAS instrument was mounted on a car roof, which allowed us to perform measurements along individual driving routes. From car MAX-DOAS observations along closed circles around Delhi, together with information on wind speed and direction, the NOx emissions from the greater Delhi area were determined: our estimate of 4.4 x 1025 molecules s-1 is found to be slightly lower than the corresponding emission estimates using the EDGAR emission inventory and substantially smaller compared to a recent study by Gurjar et al. (2004). We also determined NOx emissions from Delhi using OMI satellite observations on the same days. These emissions are slightly smaller than those from the car MAXDOAS measurements. Finally the car MAX-DOAS observations were also used for the validation of simultaneous OMI satellite measurements of the tropospheric NO2 VCD and found a good agreement of the spatial patterns. Concerning the absolute values, OMI data are, on average, higher than the car MAX-DOAS observations close to strong emission sources, and vice versa over less polluted regions. Our results indicate that OMI NO2 VCDs are biased low over strongly polluted regions, probably caused by inadequate apriori profiles used in the OMI satellite retrieval. [ABSTRACT FROM AUTHOR]

The present study focuses on spatial patterns of urban heat island (UHI) development within the rapidly changing urban landscape of the Delhi Metropolitan Region (DMR). To determine the role of local environmental factors in the shaping of microclimatic conditions, automated weather sensors were installed at 13 sites for a one-year period from May 2007 to June 2008. The results indicate significant differences in observed near-surface temperatures among the different stations. The UHI effect was more pronounced in the late afternoon and nocturnal hours. The highest temperatures are observed in the northern and western sections of the study area, which overlap with high-density residential and industrial land uses. Furthermore, these areas also experienced extreme high temperatures of prolonged duration during the daytime, increasing heat-related risks in these areas. At the seasonal level, the greatest differences in temperatures were observed during the summer, likely due to the predominantly clear sky conditions. However, areas of higher temperatures were relatively localized during the cooler months of the year. [ABSTRACT FROM AUTHOR]

A solar dryer integrated with photovoltaic powered DC fan has been designed and installed at Solar Energy Park, Indian Institute of Technology Delhi. The dryer has been coupled to a solar air heater having blackened surface of absorber for improved energy collection efficiency and a drying chamber with chimney. An analytical expression for characteristic equation for photovoltaic/thermal mixed mode dryer has been derived as a function of design and climatic parameters. The experiment was carried out for forced mode under no load conditions during April 2008 and validated with theoretical results for New Delhi climatic condition. This paper also shows the detailed analysis of thermal energy, exergy, and electrical energy gain by considering four weather conditions (a, b, c, and d type) for five different cities (New Delhi, Bangalore, Mumbai, Srinagar, and Jodhpur) of India. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The present communication presents fault plane solutions of 19 earthquake events (ML ≥ 3.0) located in Delhi and its environs in the Delhi Fold Belt (DFB), recorded by 16-elements Seismic VSAT Telemetry Network in and around Delhi established by India Meteorological Department. The fault plane solutions based on P-wave polarity demonstrate that earthquakes in the DFB have a dominant mechanism of thrusting with minor strike-slip components; the nodal planes conform to (i) the Mahendragarh-Dehradun Subsurface Fault trending NNE-SSW and (ii) the Delhi-Sargodha Ridge, trending NW-SE. This communication further analyses seismotectonics of DFB vis-à-vis seismicity pattern. [ABSTRACT FROM AUTHOR]