There are three main types of rainfall:

1. **Convectional Rainfall**: This occurs when the sun heats the Earth’s surface, causing warm air to rise. As the air rises, it cools and condenses, forming clouds that result in heavy, short bursts of rain. Common in tropical regions.

2. **Orographic Rainfall**: This happens when moist air is forced to rise over mountains. As it ascends, it cools and condenses, leading to precipitation on the windward side. The leeward side often experiences a rain shadow, resulting in dry conditions.

3. **Frontal Rainfall**: This occurs when warm, moist air meets cooler air, causing the warm air to rise. As it rises, it cools and precipitates. This type is common in temperate regions, particularly during weather fronts.

Each type significantly influences climate and ecosystems.

Metamorphic rocks are formed from the transformation of existing rock types under high temperature and pressure conditions. Their characteristics include:

### Characteristics:
1. **Texture**: They often display a foliation (layered appearance) or a non-foliated structure.
2. **Mineral Composition**: Common minerals include quartz, feldspar, mica, and amphibole.
3. **Hardness**: Generally harder and more durable than their parent rocks.
4. **Color Variations**: Can range widely in color due to different mineral compositions.
5. **Cohesion**: Increased density and strength compared to parent rocks.

### Classification:
1. **Foliated Metamorphic Rocks**: Characterized by a layered or banded appearance.
– Examples:
– Slate (from shale)
– Schist (from shale or granite)
– Gneiss (from granite or sedimentary rocks)

2. **Non-foliated Metamorphic Rocks**: Do not exhibit layering and have a more uniform texture.
– Examples:
– Marble (from limestone)
– Quartzite (from sandstone)
– Hornfels (from various parent rocks)

These classifications help in understanding the conditions of formation and the properties of the rocks.

सीमेंट उद्योग निर्माण सामग्री का एक महत्वपूर्ण क्षेत्र है, जो भवनों, सड़कों और अन्य संरचनाओं के निर्माण में उपयोग होता है। यह मुख्यतः चूना पत्थर, मिट्टी, और अन्य खनिजों से बनाया जाता है। भारत में सीमेंट उद्योग तेजी से विकसित हो रहा है, जिसमें उच्च गुणवत्ता और उत्पादन क्षमता पर ध्यान दिया जाता है।

पश्चिमी बंगाल के हुगली भूभाग में पटसन उद्योग की सघनता के प्रमुख कारण हैं: उपयुक्त जलवायु, गंगा नदी का निकटता, अच्छी परिवहन सुविधाएँ, कच्चे माल की उपलब्धता, और सस्ती श्रम शक्ति। यहाँ की प्रौद्योगिकी और औद्योगिक बुनियादी ढाँचा भी इस उद्योग के विकास में सहायक हैं।

The Western Ghats are higher and wetter, running parallel to the western coast of India, while the Eastern Ghats are lower, discontinuous, and drier, situated further inland. The Western Ghats host rich biodiversity and dense forests, whereas the Eastern Ghats have more agricultural land and less dense vegetation.