Social Science 4 Marks Each

Impact/effect of climate on human life are as follows:
→ During most of the year, the temperature remains high in India, so different crops can be grown.
→ Rain in the country is very irregular. This fluctuates the crop production. As a result, a condition of shortages and drought occur frequently in many parts of the country.
→ Most of the rain in India falls during monsoon season, so on the basis of rainfall, only one crop can be taken in those regions where the irrigation facility is not available.
→ The onset of the end of the monsoon season is uncertain. So if water is not available at a proper time, sowing cannot be done or the ready crop is destroyed. This causes adverse Impact on the agricultural production.
→ Sometimes torrential rain creates a flood like situation. This also destroys the ready crop.
→ Soil is eroded due to the floods in the river. The soil fertility decreases and the crop production is also decreased.
→ After the monsoon season is over, a problem rises regarding the employment of the agricultural labourers. They migrate to cities for employment.
→ Due to the uncertainty and irregularity of the rain, industries dependent on crops like cotton, sugarcane, tobacco, etc., do not get their raw material. So these industries have to suffer.
→ Due to inadequate rain, many areas in India face the shortage of drinking water even today. people have to struggle very hard. The life of the people living in desert and at the foothills of mountains becomes full of hardships. It is difficult to save the animals.
Thus, climate has an immense impact on human life. It directly affects the food, dress, occupations and dwellings of man.

It is winter season in India between December to February.
→ At this time, the sun rays fall slant over India so the temperature remains low. The north-east winds blow over India during this season. As these winds blow from landmass, these are dry and cold. So on the whole the climate of India during winter is dry and cold. The sky is clear in the absence of the clouds. The air does not contain much moisture. As a result. the climate in India during winter is pleasant and healthy.
→ The winter temperature in north India is very low because these regions are far away from the sea and some part of it is sandy.
→ The winter temperature decreases from east to west in north India. In January, the temperature is 18 °C at Kolkata, 16 °C at Allahabad and less than 10 °C at Delhi.
→ At this time, very low temperature prevails over Himalaya. The temperature at Shimla and Darjeeling remains around 5 °C.
→ Sometimes there is very heavy snowfall in Himalayas during winter.At that time, the cold and heavy air rushes towards the northern plains. A very heavy cold wave prevails over north India as well as Rajasthan and Gujarat and the temperature drops down suddenly. Some parts experience frost due to which crop like cotton is damaged.
→ Except for the high mountains, the temperature during winter does not fall up to freezing point In India, because the Himalayas, situated on the northern boundary, prevents the extreme cold winds coming from central Asia and protects India from chilling cold.
→ South India lies in torrid zone. Besides. It is also a peninsula. Its interior parts are not much far from sea. So it is not as cold as northern India. e.g., The temperature of Kochi in January is 26 °C, Madurai is 25 °C and Chennai Is 24 °C. The winter temperature decreases from south to north in India. e.g.,the temperature In Delhi is less than Mumbai.
→ The north-east monsoon winds. blowing over most of the regions in India in winter, are dry as they happen to come from land. That is why they do not bring any rain. But they bring rain on Coromandel coast as they happen to come over from the Bay of Bengal. These winds also give heavy rain along Tamil Nadu coast. Besides this, the mild atmospheric disturbances from north-west in winter bring some rain in the west. This winter rain benefits the crops of wheat and gram in Punjab and Haryana. Other parts of India get occasional rain during winter. In Gujarat it is known as 'Unseasonal rain' or 'Mavthu'.

This season prevails over India during October November.
→ After September, the temperature decreases in India and the vertical sunrays gradually shift to southern hemisphere. This results in the development of low pressure over the Indian Ocean in the south and high pressure over northern India. As a result, the south-west monsoon winds blowing during monsoon season become weaker by the end of September, and in October these winds retreat and start blowing towards the sea. That is why the time duration between October November is known as 'Retreating monsoon season.'
→ In north India, these winds blow in the form of a mild cyclone and give rain in Punjab. Haryana. Himachal Pradesh. etc. which benefits the Rabi crop.
→The winds blowing from south-west during monsoon season change their direction and now blow from north-east. They pass over the Bay of Bengal and gather moisture and give good rain along the Coromandel coast of Tamil Nadu. This season is considered to be the rainy season of Tamil Nadu.
→ During October - November a season of dry and cool winds starts in place of humid and hot rainy season. A primary characteristic of this season is the clear sky and increasing temperature. The temperature increases due to the clear sky but nights are cool and pleasant. The soil is still damp so the air also contains more moisture. Due to high temperature and more humidity, the day time weather is very perplexing. This situation is known as 'October Heat' In Gujarat it is known as Bhadarvi Taap.

For an agrarian country like India, the rainy season (monsoon) is the most important season. During this season, which stretches from June to September, the country gets about 80% of its rain. The agriculture in India depends very much on this rain.
→ Rain during the monsoon season is very much dependent on the south-west monsoon winds blowing towards India. This rainy season is also called as the season of 'North-West monsoon winds'.
→ In the north-western plains, a low pressure condition develops due to high temperature by the end of May. At this time, high pressure prevails over the Indian Ocean situated to the south of India. So winds blow from the Indian Ocean towards the low pressure in north India. These winds bring enough moisture with them. So India gets rain during June to September.
-These winds are not as regular and permanent as the Trade winds. They originate and blow during a specific season only, and that is why these winds are known as 'Seasonal (Mausami) winds'.
The south-west monsoon winds bifurcate into two branches due to the Indian peninsula: 1. The Arabian Sea Current and 2. The Bay of Bengal Current.
1. The Arabian Sea Current: These winds enter India through Kerala situated on the western coast of south India. The Western Ghats obstruct them as soon as they enter the coast. This gives more rain on the windward side of Western Ghats After crossing the Western Ghats when these winds reach Deccan plateau, there is little humidity left in them. So the amount of rain decreases. The Deccan plateau lies on the leeward side of the Western Ghats so it becomes rain shadow area. Mumbai and Pune are not far from each other, however Mumbai which is situated on the windward side of Western Ghats gets more than 200 cm rain, while Pune on the leeward side gets less than 75 cm rain.
→ On the western coast of India, rain decreases from south to north from Kerala to Karnataka, Goa and Maharashtra.
One branch of the monsoon winds advances through Narmada valley in Madhya Pradesh. When these winds advance. the winds from the Bay of Bengal merge with them.
→ One weak branch of Arabian Sea goes towards Gujarat. Saurashtra and Rajasthan. It contains less humidity. Moreover, there are no high mountains or dense forests in Gujarat. So there is little possibility of condensation of the humidity. As a result. Gujarat gets less rain. When these winds reach Rajasthan. there is very little humidity within them, so there is less rain. The deserts of Rajasthan get even less than 10 cm rain.
2. The Bay of Bengal Current: These winds first enter West Bengal and reach up to Meghalaya. These winds are full of moisture. These winds are obstructed by Garo. Khasi and Jaintia hills in Meghalaya. So the windward slopes of these hills get torrential rain. Cherrapunji. situated on the slopes of Khast hills. gets about 1200 cm rain annually which is highest in the world. Mawsynram, situated 16 km far from Cherrapunji. is also famous for maximum rainfall received during 24 hours.
→ When the direction of the winds blowing towards west changes, their direction becomes south-east. These winds pass over West Bengal, Bihar. Uttar Pradesh and Haryana and reach Punjab The moisture in them eventually decreases as they advance towards west. So the rain in the northern plain decreases while going from east to west. Kolkata gets 160 cm rain. Allahabad 100 cm and Delhi gets 65 cm rain.
→ When the monsoon winds coming from the Arabian Sea and from the Bay of Bengal merge they give good amount of rain in northern Himalayan area. Sometimes the rain here is in the form of snow.
→ Most of the rain in north India is brought by winds coming from the Bay of Bengal. The cyclones originating in the Bay of Bengal also play an important part in bringing rain. In the northern part of the Bay of Bengal a low pressure is developed and five to six cyclones are formed during the monsoon. These cyclones advance towards west along with the monsoon winds and become much useful to bring rain. Sometimes the impact of these cyclones reach even up to Gujarat, which gets rain.

The summer in India prevails from March to May. It is prolonged up to June in the north-western part of the northern plain.
→ At this time the sunrays in India are vertical so the amount of heat is more. In south India, severe heat is experienced in the month of May. The summer temperature of some places here remains as high as 40°C. Severe heat is experienced in central and north-west India in April and May. The temperature reaches its extremity in May. The maximum temperature of some places rises up to 40°C to 50 °C. (Sri Ganganagar has recorded a high temperature of 51 °C). Thus very hot weather is experienced in summer in India.
→ In comparison to north India, the temperature in south India is less. Its proximity to sea and the height of the plateau make the summer of south India milder. e.g., The summer temperature of Delhi and Allahabad is about 34 °C. while it is 27 °C at Bengaluru and Kochi and is 30 °C at Madurai.
→Overall, the summer is hot and dry over most of the regions in India.
→ There is not much rain during summer in India. But sometimes, rain occurs along the Malabar coast in May which is called 'Amra Vrushti. It helps to ripen the mangoes.

The noteworthy characteristics of Indian climate are as follows:
(1) The climate of India overall is hot. Except for the high mountainous regions in the north, the temperature never goes below 0°C during winter in other regions.
(2) The coastal regions have a temperate. humid and moderate climate, while the regions away from the seacoast have a drier and continental climate.
(3) Wind changing direction according to the season is the main characteristic of the climate of India. At the end of summer, winds blow from sea to land and during winter the winds blow from land to sea. So, the rain in India falls during the rainy season at the end of summer and during winter except for the eastern part of Tamil Nadu. rest of India is almost without rain.
(4) According to the climate, there are four seasons in India: 1. Winter- December to February. 2. Summer-March to May, 3. Advancing Monsoon-June to September and 4. Retreating Monsoon-October and November.
(5) Maximum cold is experienced in the northern parts of Himalayas whereas the maximum heat is experienced in Rajasthan. During winter, the temperature of Dras in Ladakh goes down up to -45°C while Sri Ganganagar in Rajasthan records temperature as high as 51°C during summer.
(6) Winter in India is energetic and healthy. During this season, winds blow from north-east direction which are dry and cool except for the Coromandel coast.
(7) Summer in India is hot, dry and. perplexing season. In north India and specially in its north-west part, its immense impact is felt. The summer in south India is comparatively moderate.
(8) In India, monsoon (rainy) season is the most important season. The south-west monsoon winds blowing during this season bring rain in entire India. Most of the annual rain is received during this season.
19) There are regions in India getting maximum as well as scanty rainfall in the world. Annual rainfall in Meghalaya is about 400 cm. while Leh in Ladakh and Rajasthan deserts get 10 to 12 cm rainfall annually. Cherrapunji and Mawsynram in Meghalaya receive about 1200 cm rain, which is the maximum in the world.
(10) As most of the rain in India is received through monsoon winds. an uncertainty always prevails about the amount and the time of the rain.