Atoll is a low island found in the tropical oceans consisting of coral reefs surrounding a central depression. It may be a part of the sea (lagoon), or sometimes form enclosing body of fresh, brackish, or highly saline water.

During its revolution around the sun, the earth is farthest from the sun (152 million km on 4th July). This position of the earth is called aphelion.

Cumulus clouds look like cotton wool and have a flat base. They exist in patches and can be seen scattered here and there.

The land mass of India has an area of 3.28 million square km. India’s total area accounts for about 2.4 per cent of the total geographical area.

From west to east Tropic of Cancer passes through Gujrat, Rajasthan, Madhya pradesh, Chhattisgarh, Jharkhand, West bengal, Tripura and Mizoram.

Standard Meridian of India (82°30'E) passing through Mirzapur (in Uttar Pradesh) is taken as the standard time for the whole country.

The Satluj, the Beas, the Ravi, the Chenab and the Jhelum join together to enter the Indus near Mithankot in Pakistan.

Ambala is located on the water divide between the Indus and the Ganga river systems. The plains from Ambala to the Sunderban stretch over nearly 1800 km, but the fall in its slope is hardly 300 metres.

The Godavari is joined by a number of tributaries such as the Purna, the Wardha, the Pranhita, the Manjra, the Wainganga, and the Penganga.

Narmada creates many picturesque locations. The ‘Marble rocks’, near Jabalpur where the Narmada flows through a deep gorge and the ‘Dhuadhar falls’ where the river plunges over steep rocks, are some of the notable ones.

Tropical cyclones are violent storms that originate over oceans in tropical areas and move over to the coastal areas bringing about large scale destruction caused by violent winds, very heavy rainfall and storm surges. They are known as Cyclones in the Indian Ocean, Hurricanes in the Atlantic, Typhoons in the Western Pacific and South China Sea, and Willy-willies in the Western Australia.

A river joined by its tributaries, at approximately right angles, develops a trellis pattern. A trellis drainage pattern develops where hard and soft rocks exist parallel to each other.

According to the regulations of the Indus Water Treaty (1960), India can use only 20 per cent of the total water carried by the Indus river system. This water is used for irrigation in the Punjab, Haryana and the southern and western parts of Rajasthan.

The Arabian Sea branch reaches Mumbai on approximately the 10th of June.

Silver fir, junipers, pines and birches are the common trees of Montane Forests.